After the dialogue for the quest-giving dude in the subdungeon (I assume he's the start of the Transmuter unlock process), stepping back onto his tile will give a "Talk" option that doesn't do anything.
Perversely, the change to CYDSTEPP is going to be less of a burden to Rogues than to any other class (except maybe Monks, but they don't like CYDSTEPP anyway). Even more perversely, it makes Dracul worship (and inevitable Dracul annoyance) even more beneficial for a CYDSTEPPer.
Getting piety with Binlor is way too easy with the reduced MP cost (he was already even more mana-efficient than Mystera, now a Wizard has a 1:1 ratio of mana spent to piety gained and can use BLUDTOPOWA; you're almost more likely to run out of walls before you run out of tiles when building piety with Binlor). He should probably only give +4 or even +3 piety per casting.