I don't think there is much you can do about screaming outside other than offering activities or toys and generally trying to convince him that it's fun to be outside...aside from that I think you are just going to have to wait for him to adjust.

As for skipping am snack I have one who STILL does this but mom has admitted to filling him up with baby cereal for breakfast which explains why he is never hungry. I would try and either push am snack back even just 15 mins. However I usually naturally move lunch 15-30 mins instead when I have a little one because I try and get them to bed 1/2 hour earlier since I find that they usually need the extra sleep anyways (I don't really do morning naps).

Good luck...I am going to be starting two new ones this summer and I am keeping my fingers crossed for easy transitions as I have one who took a very long time to adjust and it was painful...I really don't want to go through that again!