i'm not sure how to call this one. I'd say General, or for a more "I like Bel" term, Dedicant. That way you're dealing with someone who probably gets nothing more than a nod from Bel.
I'm going to comment on the fact that compared to the original classes [which aren't powerful but are so damn interesting and awesome that i honestly couldn't care less, plus they do insideous well], this is ludicrously powerful, especially now that you've added bonus feats and sneak attack to it. Yes, i know these help them rather than their allies like the others but what ya gonna do?
If you wanted an ACTUAL Disciple of Bel, likely if would be geared in such a way that it could build a militant cult rather than the tactician that this is: an ability similar to Mass Rage/Suggestion that allows you to stoke anger and martial pride, the ability to train peasants really fast, heroes feast in there somewhere and some stuff to define the slippery gittishness of Bel's foreign policy.