(Edit: this is a reply to a now deleted comment)
Holding money like that is a legal and tax minefield, which is AFAIK why LiberaPay stopped trying to do similar things.
But even if you figure out some way to make it work without a banking license, you still will need some sort of formal non-profit organisation to run it.
Call me jaded, but such non-profits usually become self-perpetuating entities more concerned with paying salaries of their administrative staff than furthering the original goal.