Which faction for the first game

[Advo-san]

Spanish are definitely a good faction to start with.

I agree, but the Almohads are also good for the same reason. Using Granada (in VI) or Granada and Murcia (in XL) as a border line, you can take up the task of uniting all muslims under your banner (see: destroy the eggys and turks), stabilize a borderline in Constantinople and Khazar, and after that I would suggest you followed the footsteps of Abdel Rachman untill the whole of Europe becomes a tranquil, orange empire!