It's all anecdote, so it really just depended on who was around me, and what kind of a relationship we established. And, most importantly, who they are as a person, beyond their type.
Question 1: Which NT types do most ENTP get along with? Why?
My grandfather was an INTP (my INFP mother's father); I loved sharing silence with him, as much as I loved listening to him drone on about a philosophy or thought or idea, in minute detail, because the way he spoke of it, was actually really interesting, if you chose to be actively listening. I really found it amusing how detached with "daily" life he was, and how inconsequential he saw most things that would have others scurrying like a chicken with their head cut off. E.g., him getting a SUBSTANTIAL amount in change back from grocery shopping, and going through the motions of putting it in his pants pocket, only to have missed the pocket completely, while the change falls to the ground, for me to gleefully pick up, and him not even noticing or caring as he continues to walk on. The absent-minded professor.

However, because of this aura of "absent-mindedness", not really fully engaged in the social sphere, he can seem kind of stagnant with life and its movement. The social awkwardness was not always endearing, sometimes, it was, "REALLY? Really? You do realize you are not only living for yourself, but your actions have ripple effects in the social sphere. Wake up, and get on with some of your obligations!" I felt this especially on behalf of my ISFJ grandma, who had to thus, carry the burden of a lot of the daily living maintenance, on BOTH their behalf. And, his introvertedness was sometimes draining to me. He could also have a tinge of pessimism and this aura of not really caring about any one or any thing unless they were an idea to be thought about. It almost seemed like he would have done well to live as a hermit, so that the side-effects of his ways didn't inadvertantly burden my ISFJ grandma (who could have spoken up, but, chose not to, because she loved him and knew him enough, and accepted her life as that reality).
ENTP - I am, therefore, I become.
My SO is INTJ. He's like a mirror reflection of me. We each are, in turn, frustrated, puzzled, and, intrigued, by how the other could POSSIBLY go through life the way they are. He challenges me, as I challenge him, which I love. We have issues with being emotionally vulnerable with each other, but, slowly and steadily, the child in us, afraid of getting hurt, is laying bare to the other. I get frustrated by his patronizing ways, and he gets frustrated because he can't corral me (although a J-part in him, wants to try, because things would go that much more efficiently, if he could). In turn, he gets frustrated because if he patronizes me, I mock him and his SERIOUS BUSINESS IS SERIOUS and, through action, point out how flawed his Te-plans really are (Ti is really good at finding gaps). But, we're getting better at leaving those childish things behind. We are very acutely aware of each other's weaknesses, even though we know each other's strengths, the other's weaknesses are more deeply realized. Which, in a positive turn, allows for much growth. Substantial growth, once commitment is there. And, we can be chillike together, like play-mates, because Ni gets shyly intrigued by Ne's flamboyance and seeming outward self-assuredness, and wants to join too, at first, protesting, then, hesitantly so, with a bit of goading, and Ne is all too happy with a playmate, and appeases Ni's need for bringing it out of its shell, because the payoff for Ne is great, because with Ni having the capacity to be so wacky and weird and quirky, once it gets going, there's nothing more motivating for Ne....The different sameness intrigues us.
I have a close ENTJ friend, and it's weird, because even though they're xNTJ, and they see the same issues in me as the INTJ (INTJ refers to me, as: Personification of Chaos, or other such names that inevitably includes the word CHAOS), there is still a respect of equals for each other. But, because there is almost a recognition of strengths in each other, our weaknesses are sometimes dusted under the rug. It's as if we want to keep seeing the other as this enigma of strength. We would thus probably make formidable enemies if things took a turn for the worse. But, I can't see that happening. We're both very open to hearing the root of where the other is coming from. She has such a heart of gold, so accomodating to everyone, and getting stuff done, but, firm in establishing her boundaries (in a very determined, diplomatic way)......I respect her, greatly. One thing though, about her, she panicks way faster than I do, like the INTJ, but, unlike the INTJ, she has way less of a "vision" of how to get out of the rut. She just keeps doing, hoping to get a hit, once panic sets in. She can also get emotional, but unlike my ENFJ friend, her emotions seem almost juvenile to me (somewhat like the INTJ, but more so).
Question 2: Which NF types do you have conflicts with easily? Why?
My mother is an INFP, and I

her, although she irritates me at times, with the way she reaches conclusions. When we fight, it's rare but all the more scathing for it, where I get really really aggravated by her bringing up the past, in what I would consider, irrelevant-to-the-topic manner., with the aim to either hurt with a zing or show a depth of her own hurt. And she tends to move away from the main topic of discussion, without needing a clear-cut resolution for it (which I really need). However, overall, we get along quite well. I am charmed by her "Ne-musings" as she is mine, and we find the simplest things in life to have a life of its own, with its hidden charms, which is awesome when we converse. Because, unlike with others, where talking about each other's day seems almost like a narrative, ours are filled with hidden meanings, charms, colours, wonder, shared laughs, and just this great aura of optimism. Which I really really appreciate. So, my relaying to her that I had to "walk in the rain to work today", goes from a boring story (as it would be, if I relayed it to most others), to quirky little observations, connections, metaphors, and all things layered and fun about life and its charms and sense of wonderment. The way she bounces back my Ne to me. She is a dreamer and, although I am not "seemingly" as much of a dreamer as her, because I have an "edge" to me, a sense of dry reality; with her, I can explore that side of mine, with abandon.
One of my best friend is an ENFJ, and her and I are very in-sync with each other. We're like each other's soul-mates. It's kind of awe-inspiring how we get each other's most obtuse, out-there thoughts and musings, and sum up exactly what the other is meaning, so, very well. She is a great therapist for me.

But, when we fight, people clear the area (I get more and more cold, flippant and derisive and she gets more and more emotionally volatile; it's not pretty, and we're both extremely stubborn). She is one person who can keep up with me in a debate (speaking in terms of longevity, like hours and hours, turning into days). I do get irritated sometimes by how much she cares about what others think of her, how her image is perceived (in, what I consider, inconsequential spheres, in life).
Had a really close INFJ friend. I liked how deeply she cared, and was accomodating, but there was a detachment to her. And, she reminded me a bit of Eeyore (from Winnie the Pooh), which made it draining to be around her for me, as an ENTP. It was as if she deemed herself to be Sisyphus, when she took stock of the world, and her lot in life. It got tiring. I still think of her fondly, and wish her well, but, it was too much effort trying to break through the wall, and "proving" myself worthy to get into her inner sanctum, where it felt like an unbalanced relationship. And a test. So I drifted apart. We still connect every so often, but it's on a superficial level.
My other best friend's sister is ENFP, and she and I often *get* each other's train of thought (like the ENFJ, but, without the depth of soul-understanding). She, like my mother, does irritate me with how she reaches her conclusions sometimes, i.e., my perception of it being irrational (and I sometimes think it's selfish, which is not something that I think about my INFP mom's way of reaching the conclusion even if both seem irrational to
me). She also has very grandoise ideas about herself, which are not really based in reality, and although we are similar in this way, while I come from a place of self-deprecation when I talk like that, she seems to genuinely believe it. So, I see her as somewhat superficial, in this regard. She also *sees* the good in everyone, when it would do her well to be a bit more wary and self-preserving, and it irritates me because, undoubtedly, it comes to bite her in the ass, and we get to hear the woes or help her clean it up. She seems like a bit of a people-pleaser to me, i.e., appealing to the emotions of others, but it rings superficial for me,and at times, reads as inadvertant manipuation. But, she is getting better at it. She is also not very reliable, like if she borrows from someone, whereas it bothers me greatly that I need to return what I owe/borrowed, it doesn't register with her. And, even though she pours her heart (feelings) into you, or a discussion.........it could end just as abruptly, and she doesn't seem affected to the degree to which she projected, in the first place. There's a dissonance there. Theatrical, like an act? But, we are awesome in bouncing the whackiest ideas off of each other, and keeping up with each other, and she's great in conflict-resolution with my ESFJ best friend (her sister), because we both get where we're coming from, especially with skipped steps (without needing an explicit detailed explanation of how we reached from A to K). Although, she does get tired of my "way of thinking", and the dry explanations (Ti-flavoured), because, although her's may not always add up, rationally, it is thus, more colourful, as it appeals to the other's emotions.But, there's almost a recognition of each other, as similar, yet vastly different, and a "SO CLOSE, but, MISS" in terms of establishing a deeper, more meaningful bond. When we converse, it's almost as if it's parallel, rather than meeting at a common point of introspection. It's hard to explain, it's as if we're so similar that the MISSES throws us off, and thus, really irritate the other, because inevitably, we realize Fi versus Ti, while our expectations of the other is to always just *get* it, BECAUSE we are so similar. She's got a huge heart, and her trusting, optimistic nature is quite inspiring, though. I think our dynamic has more to do with each other, as individuals, rather than our types really factoring into it, and where she is at the stage in her life, and where I am.