My suggestion is to assume that they can be loaded in any order by the game, that way you do not assume anything that is untrue, especially if someone chooses to rename files (and as you mentioned different platforms, could be a difference between file systems on the same platform as well (eg. ntfs vs fat32)). As we do not have the concept of unofficial patches and such I see no reason to mess with priority, it is better to talk about compatibility between mods imo. Could have it as a feature of a mod manager though, if it becomes a problem (one could look at skyrim, though there you explicitly set priority for all mods).