Thanks blackcat. DS is making progress on social/behavioral fronts, and that is honestly what he needs most right now. Notwithstanding strealth dyslexia, he is well ahead of grade level. Also - DS and Best Friend see each other in after school care, where they are both likely to be for the duration of elementary. We know the family, and they're not planning any changes. Also - while the school hasn't been wildly helpful with DS's struggles, they have been responsive when I make suggestions that keep life easy for them! So if I suggest that DS and Best Friend stay in the same class because Best Friend has such a positive influence on DS (and vice versa), they are likely to listen.
So - it looks like you are right. Maybe hold for a year.
