
I wonder if the other two civs are the SE one and the africa one? Although the "native americans" and byzantines are up for grabs too. Please PLEASE no HRE, that will be unspeakeable...
Rhye has already said the HRE is not in, and that Byzantine is only in as a non-playable civ (and doesn't count as one of the 5 new civs).
I'd go with Poland and a SE Asian civ.

Korea for sure not- it wasn't added with Warlords because it haven't enough place.