Ours is in a AR850 with 3 YoYos, 2 angels, 2 Kribs and a CAE(which by all accounts is a nono) he gets on OK, he's the resident grumpy old bugger, and has a real dislike of the bigger Krib, who he chases whenever he can but she's a lot faster than him and it doesn't seem to upset her a lot. The CAE keeps him in his place if he gets too grumpy by chasing him right back. But generally it's a peaceful tank.
My suggestion would be to have plenty of caves and to put the rainbow in last, like several weeks last, to ensure that everyone has their own spot first so it doesn't become territorial.