Sinan:
Yes, only 4 offspring per couple, but each offspring can have 4 more, so it doesn't really matter.

Also, my turkish family members are getting the ReligiousActivity trait line when coming of age, not the public faith one, but at least some piety!

I never had a trouble getting wives for my turkish men. I seem to get an offer every second turn and only the newest generation isn't married, but for catholic factions I found that to be a problem always. My heir wasn't married even in his 50s...