For NFHS I think I am going with Billy on this one. The contact is marginal to the offense but the defender is their with plenty of time in LGP prior to the shooter becoming airborne. He turns to absorb some of the contact which he is allowed by rule, but is still knocked over I don't think this constitutes marginal or incidental contact. The offense is responsible for contact once defender has LGP and remains in front of the play. I have a charge.

Would any of you be more likely to rule this a charge if it 10 feet further from the basket and a floater lay up instead of a dunk?

Marginal contact because he dunked it? Aldridge turned and was still knocked to the floor. NBA, with heels on the RA line - block.
In NFHS, it's a train wreck: PC.

Go Blazers!!

The mere fact that the defender is in the RA and ended up on the floor does not mean it has to be a block.

PC or nothing are the only to options...I got nothing as the defender got out of the way instead of being knocked out of the way.

Team B can move to absorb the contact. For that reason, I would never have a block on this play.

The only two options are a PC or a no call. My call would be a strong lean towards a no call. Contact had little to do with the play.

There are no secondary defenders when a rebounder makes an immediate move toward the basket.