To answer both ones here is why I built it the way I did.
1) I went with Thresholds instead of a block on movement becayse it effect spellcasting which is good when the Big Guy mandates my dude go after Warlock Guy, in addition to say Rampires and other mean beasties.
Additionally Thresholds would just be how its treated mechanically not thematically (which are treated as belonging to homes), I am thinking I would go with a Holy Aura thematically.
IE it repels those who would seek to do harm slowing them down if not even stopping them in their tracks.Because of this, this power would not stack with present thresholds of a home or Holy Ground which would be way OP imo, I don't need to run the super personal power, besides that is all in the actual roleplaying fluff, not the power itself, all the power is for is for the mechanics everything else you do in game. As for why he can do Insta-Sanctuary, well same way the Knights can go toe to toe with big D Dragons, Lords of the Outer Knights, and other such entities, if manifested in a different way. His Faith and the Big Guy are powerful forces in the Dresdenverse
2) It would be for antiethical beings to my Faith but also including deliberately malicious/evil spellcasters. So as a rule of thumb if the Knights of the Cross were to oppose it, my guys ability would effect them.
3) Possibly, I'll consider it.
4) Your absolutely right, and I like the name Bastion of Faith so I will go with that.
5) I like the Devout Words stunt and I'll probably end up taking it for my main defense.