I would suggest you turn the Cremean Khanate into a minor civ much like the Celts in Rfc and the Zengids in Soi. This way there would be no need for them to have a settler map as all their cities would be spawn on certain dates and balancing them would much easier. I say this because although the Crimeans were a civ the area they historically occupied was rather small and they were a vassal state of the ottoman empire for most of their history.
Other than the Crimeans, I think the following other civs should be minor also:
-Norovgorod
-Aragon
-Sultanate of Rum
These are the civs that I think should be added as major civs:
-Morocco (Almoravids and Almohads)
-Egypt (Saladin and Malmaluks)
-Prussia
I'd like to point out that in vanilla RFCE the area the Crimean Khanate controls is unstable for the Ottomans