Ifrit stops using blockable attacks when he starts using special moves. Aegis, Outmaneuver, and Deflection aren't needed for him.
Blocking does appear in the log, along with an animation.
+block rate might help, haven't really tested. There's only like one piece of gear in the game with it anyway. I've tested dex a little bit and it doesn't appear to do shit. Strength maybe raises block rate? but maybe not, I've had mixed results.
I don't know about your shield condition.
As far as I know animation lock doesn't prevent you from blocking.