the top assets should not be traded for George. He hasn't guaranteed he would sign anywhere besides LA, so the price is minimal at best.
The only chance the Pacers have to get a good haul is to keep bidding up the price until a team makes a desperate offer. The Celtics don't need to make that desperate offer because the team is already good without him.
I think the Celtics can offer one of the best packages out of the few rumored teams. It likely is because of Jae Crowder. George would obviously start at the three. With Jaylen and Jayson on the bench, there isn't a need for Crowder to remain on the team besides strong bench minutes. At that point though, he may become disgruntled, so at best he should be the centerpiece in that trade.
Surrounding Crowder, the Celtics should offer one future mid-first pick, likely the Clippers, a young prospect like Mickey, and Tyler or an expiring contract to make the money work.
Overall, it is arguably too risky to trade so much for only one season. If Ainge decides to make the move, I do think we have a good chance at convincing George to stay and compete for a title by getting him to sign a shorter max deal, so if he does want to leave after a couple more seasons he can.