If the only change you have so far is the custom .dll (needed for more civs), then you can install any mod that does not have a CvGameCore.dll on it's own on top / in addition to it. I think Diversica should be fine.
If so - just install the mod you wan't - say Diversica - and drop the CvGameCore.dll you are using now (the one for more Civ's) in that mods Assets folder.
If there is already one (custom .dll), you will need to either try another mod, or contact the mods authors about compartibility / merging / more civ version.