Go humanist, if you have the Third Rome dlc, the Orthodox bonuses to unrest will basically mean you will forget what Rebels are once you finish Humanist, Quantity and Defensive are also useful since you are constantly besieged by everyone in the region, especially once you go into Italy.
Stab cost from religious is not to be underestimated as well, allowing you to get ~10 ADM per stab lategame. It dies in 99.9% of games in the first year or two of any game. Defensive is always good early on, especially as Byzantium. The AE will rack up high with the Muslim countries when you take over Anatolia. Keep in mind Turkish will likely be an accepted culture for the entire game, regardless of your choice of ideas. Edit: just saw your point about culture conversion. Brilliant in-depth analysis regarding the usefulness of Innovative Ideas and Innovativeness Changes in 1.29. Also helps that you get a free CB on practically everybody.
