BoxRec

Is it a sanctioning body like the WBC, or a commission like the BBBoC? (I know the BBBoC also sanction fights).

If its a sanctioning body then what happens if multiple bets are on the line (e.g. Wlad), or if there are no belts on the line?

I believe it's the BBBofC for a fight in Britain, and I'm certain I e heard it said the state commissioner for Nevada does it for Vegas fights, so I can't see that there's any issue with unification fights.