I now think Drake and Ian both come back

As long as they like Hubert, anyway. Latest mock has Drake at 26 and Ian 2nd round at 33.

That would be around $2m in salary. I assume they can get at least $1m NIL staying - probably more. If they then move up to around 15th in the next year draft, that roughly doubles their NBA starting salary. If they move up to the lottery, they get $5m-ish minimum.