Response to your original post.
As I said about this sound exactly like my DS16. High anxiety upon changing schools when he was young. Introvert, gifted, perfectionist (in the way that he'd rather do nothing than turn in work that isn't perfect), and can't/won't answer questions like "what is your favorite", what are your "hopes and dreams". We had a terrible time when DS was in 7th grade health and his teacher wanted to play unprofessional psychologist. He absolutely refused to write a journal about personal questions and turn it in to the teacher everyday. (I managed to get him moved out of a class with that teacher.) And his first day of gifted class in 4th grade when he wrote two sentences when asked to "tell the teacher about himself" while the other students wrote pages.
What we put in DS's 504 last year that seemed to help for the "what is your favorite type question" was getting requiring the teachers to re-frame prompts/questions like this for him. Changing prompts like "hopes and dreams for kindergarten" to something a bit more pragmatic like "draw me 3 things you want to learn in kindergarten this year". I have been working for years on getting DS to be able to re-fame these types of questions himself. That when a teacher asks for his favorite he doesn't need to take this word literally. His teacher doesn't really care if his favorite animal is a dog, cat, pig or bat they just want him to draw an animal of his choosing. The words "favorite" or similar in a prompt has been quite an issue for us over the years. Some teachers seem to LOVE the word and don't seem to understand how much this word gets in the way for DS.
I also sounds like some of your DS problems probably do have to do with all the changes. My son has always gotten high anxiety around big changes like this and it's manifested in different ways at different ages. If this is a case you need to give him a few weeks for things to settle down. I hope things are getting better. I don't mean to scare you by saying that we are still working on these things with my son, but I didn't really realize how much of an issue they were with him till he was older and would write nothing to a writing prompt.
Good Luck
