These are both pretty reasonable. Honestly I go back and forth with Anna between the ExFP types, though you do bring up the point of her blatant naitivity which does resemble the inferior Si lack of handle on reality, though I wonder if it's that or the fact that she's been locked in a castle her entire life. ESFP definitly isn't anti daydreaming, as I also know more Fi heavy ESFP's who are very much inclined to daydreaming. Her whole leaving the kingdom to Hans seemed to definitely indicate some inferior Pi function for sure, it very well could be inferior Si. I don't really have a great argument for this atm, perhaps I'll get back to you on this.
Olaf is an interesting character, my "knee jerk" reaction when watching the movie was to say ENFP when that perhaps is not the case. I think the second movie showcased some kind of Si usage as he really does tend to get stuck in comfort and a desire for things to just say the same and predictable, similarly to Anna, which is actually a very underdeveloped Si thing to do. I do think he's relatively sensation oriented, as even his whole idealization of summer and delusion really had to do more with lack of experience than idealization (and being that he has some sort of ennea 7 influence in there somewhere, that brings along it's own edge of idealism), but at the same time I'm not sure if it's quite Se? Again, crappy argument for me, I haven't thought in depth about these characters in particular because they're not incredibly complex characters.
I agree wholeheartedly with Fe aux (I pegged her ISFJ initially in the morning as was kind of shocked she was getting pegged as a high Te user), but I'm not entirely convinced of Ni over Si. In part, duty isn't really isn't a necessary trait of Si dominance (that's more of an enneagram 1,2,6 thing that by correlation gets aligned with Si I think). In both traumatic and non-traumatic situations, I've personally seen many high Si users abandon duty and responsibility, be it because it was an annoyance/uncomfortable, because they felt incompetent or unskilled, because they desired something more in the realm of their interests or strengths, personal trauma, etc. Especially since her home life was filled with calling her dangerous because of her abilities and also being locked in her room away from others, I really don't think any type would want to stay and lead a land they don't know that well and has left them with like... A clear anxiety disorder sort of thing and trauma. I believe her feeling misunderstood also comes from this rather than being connected to type. Si as a type is characterized by an awareness of the physical (and typically personal comfort by extension) and perceiving the world in a way that is passed through the lens of experience and sensual experiences (including emotional ones). When Elsa escapes on her own, she builds herself a castle because that's what she's most comfortable with (I stand by the argument that that's connected to where she has been brought up) and she continues to indulge herself in her comforts, which includes being alone where she can control her entire environment, keep herself safe, and do whatever she wants to do, responsibility free. I'd be curious of the future orientation, I don't think it's far fetched at all, but also I don't quite remember where this could be acquired (I haven't watched the movie in awhile). Si isn't not future oriented either, however there is a directional focus of Ni that I don't see as implausible from her. I didn't really gauge her as super self trusting either, but she does seem to be moved by at least a sense of spirituality, which I'm unsure whether or not relates to her special abilities and being the "5th element" or whatever she was declared in the second movie or her actual self trust. Her desire for change and distaste for how things were sort of lead me to look back to the first movie and the fact that she never really was comfortable being Arindales queen in the first place, as well as maybe her own personal development, but it very well could be Ni from her. I'm unsure if her character was consistent from one movie to the next, but it didn't seem too off.
Sorry for like textpost, I like debates and I'm stuck in my house haha. If you'd like I'd love to hear your take with Ni, however you have no obligation to respond.
Quite honestly he's not an easy read, I figured that some ST temperament would work for him in general. ISTP doesn't seem too bad a fit, and I have no argument for anything else outside of that it seemed ISTJ could be plausible? I don't get a strong read on him at all and honestly I have no issue with ISTP.