If you use a body replacer, the installation order is as follows:
1. Body replacer
2. (optional) Any specific textures you want to use with said replacer
3. OCO
4. OCO optional textures for the given replacer

Due to the nature of this mod doing HUGE changes to all vanilla races there are bound to be compatibility issues. Things OCO will not work together with out of the box:
-Vanilla head texture replacers (most races have been rerouted to use their own texture filepaths)
-Eye and hair mods that affect vanilla races (unfortunately they all try to modify the same race data and one overrides the other)
-Vanilla NPC replacers
-Mods that edit racial stats
-Mods that replace age slider assets