Here's a more detailed critique:
1) my feelings are easy to describe in words (conversationally, not in writing)
a) often
b) not often, but more so in writing
Seems like this is a problem, since not all Fi types tend to favor expression via writing. To stereotype some, I doubt the majority of ESFPs, for example, find writing to be the best way to express their emotional state. An ISFP might just as likely favor some non-verbal medium. An INFJ might find writing helpful. Seems too muddled to make a good determining question.
2) I empathize with people by
a) taking on their feelings as my own
b) thinking about how I would feel in that situation or drawing from experience of how I've felt in that situation in the past
Again, I'm not sure this distinction is a clear one. I think emotional empathy happens for most healthy people, so everyone everyone tends to "take on feelings as their own" in a sense. I think Fe is more likely to want to help practically (which in some ways emphasizes the distinction between the helper and helpee, and in another way treats the issue as a shared problem), but Fi is more likely to emotionally commiserate... although both express warm concern. And, again, I suspect the NFPs tend to imaginatively enter into scenarios more then SFPs do, who respond more to the immediate cues.
3) my emotions show a lot on my face
a) YES!
b) not usually
Again, I think it depends. I think I personally tend to be all or nothing as far as emotional expression. If I don't feel safe I express little, but around people I trust I've very emotionally expressive. Still, what emotions i do express are usually genuinely felt. Given that, I have no idea how to answer the question.
4) I am good at tailoring my behaviors and demeanor to various social situations
a) yes, unless I am with a really mean spirited group of people
b) no
Again, I think many FPs can be extremely accommodating until a value is hit. My ESFP oldest brother has a way of blending in and being charming and funny that's almost frightening... he'll quickly adopt mannerisms and speech patterns of the group he's interacting with. Now, I don't think he's as good at knowing and applying the unwritten social rules as an ESFJ would be, but I'd think he'd answer (a) here. I tend to be very accommodating (in an INFP kind of way) and do respond to social feedback pretty quickly. However, I'm pretty inflexible when it comes to something I value.
5) I place higher priority in
a) unity, team work, external harmony
b) self expression, internal harmony
One of your more clear questions, I think. Still, one have an Fi-ish value of harmony with others, or just have an aversion to unnecessary discord.
6) my feelings come from
a) my heart
b) my gut
Already addressed in previous post.
7) I care more about
a) how a decision will effect people's feelings and well being
b) the principle of the matter.
That's a tough one for me, because one of my values is not harming others unnecessarily (including emotionally). The issue has to be reasonably serious before I will upset others... so that's a principle for me. If people "stir the pot" for no reason but their own amusement, I find that infuriating. So, given that, I tend to always factor in other people's well being, because, for me, it's a core principle.
Conversely, and TP would likely say "b," as would many TJs, I suspect. "Principle" can just as easily representing a Thinking one as a Feeling one.
8) the external world has a strong impact on my feelings
a) yes. I am adaptable, but also easily effected
b) no, though I tend to gravitate toward places with a similar vibe to how I already feel
Of course the external world has an impact on emotions. One's environment ALWAYS does (whether one is consciously aware of it or not). One may select and environment that intensifies one's emotional state, but I hardly see that as Fi v Fe. Now, I tend to know my emotional state and what's effecting it and why... but that doesn't really fall into a or b.
9) my beliefs come more from
a) how I was raised, community values, how things effect people
b) myself. even from a young age, I've always had strong views that sometimes differed from what I was taught. I can't really explain it, they were just "there"
This doesn't seem to be a great question, given that everyone (yes, even you), absorbs many values through his or her upbringing. In some ways, FPs can take such values more to heart, since they tend to be less socially practical than FJs. I know I took my fundamentalist religious upbringing very seriously, and it was heart-wrenching to come out as gay, because I'd internalized so many of those values so deeply (even compared to my straight brothers). Still, I had plenty of values of my own that were discordant with my environment... but we're all a mix of external and internal influences. In some ways, this could be interpreted as an E vs I questions, since introverts often (but not always) feel the gulf between persona and true self more keenly.
On the whole, I thought a lot of the questions showed an NFP bias for the Fi choices. I was puzzled about the "why" behind a number of the questions.