What a way to freak out a mom with a single question...I hope you get some answers.
Aishamama, I am glad you are making progress, as stated in your other thread, and are on the road to getting evals. I do not live in the US but I have also found that getting psych evals set up seemed to be much harder than other health appointments. maybe it was just the useless staff at our university medical center.
With regard to the question "take DS2 out of preschool or not", 8-3.15 sounds like a loooong day for a sensitive, anxious 4 yo who isn't really happy and socializing well. My DS, during his worst phase, would not have been able to take preschool that long everyday without acting out, badly. Maybe you can compromise with the school on shorter hours for the time being, even if you have to pick him up outside of regular pickup times? If they are wondering whether he needs to leave they might be willing to negotiate so they won't lose your tuition and feel bad about adding to the burden of a very busy mom and have a somewhat easier child to deal with?
And with a little giftie, never forget to check out the blood sugar angle - google reactive hypoglycemia. DS reacts intensely to low blood sugar and can freak out simply because he needs a protein snack but he would never think of it himself, or realize he was actually hungry. Occasional afternoons at preschool are always a bit iffy behavior-wise because we never know whether he is eating a proper lunch at school. At home, I still have to basically shovel the food into him at lunch because he is wiped out and distracted after a morning of having to socialize. Good thing the baby is good at feeding herself so I can help the 5 yo. *rolleyes*