2) No idea why we'd give him this many combos of bluffs in this spot. Although we were already HU, the fact I called a c-bet whioch he made into 2 other opponents, one being a cold caller is still relevant to his bluffing frequencies and should make them a lot lower than if I were to just flat a c-bet tha the made in a 2 way pot.

I feel your range is a bit too optimistic even though he probably doesn't have sets here too often. Also doubt we see hands like 66 or QJs.