I absolutely think the Cavs would trade Mobley for Giannis. Probably not much more other than filler to match salary, but the Cavs would go all in for Giannis. Garland, Mitchell, Giannis, and Allen would be a clear favorite in the east and perhaps all of basketball.
The Cavs could not do that trade even if they wanted to due to being in the 2nd apron of the luxury tax.
well they could if they found a third team that allowed the Cavs to dump enough salary
I mean for example, something like this works
Cavs - Giannis
Bucks - Mobley, Tyson
Nets - Hunter
Cavs drop 1.8 million below the 2nd apron and thus can do that trade, though would need to add players so might have to drop a bit more salary (they could send Strus to the Bucks and get almost 18 million below the 2nd apron - as an example). In fact, the Bucks have 3 more players than they could if they took Mobley, Tyson, Strus or with players going back Hunter, and thus could send 3 lower salary players to the Cavs (a whole bunch of vet minimum players can be traded within the next week by the Bucks).
So expanding the trade
Cavs - Giannis, Thanasis, Prince, Anthony
Bucks - Mobley, Hunter, Tyson
Nets - Strus
Picks could be added if necessary. The Cavs would still need to add 2 free agents but have almost 10 million in wiggle room below the 2nd apron so they could do it.
Cleveland would do that even though they give up Mobley and quality depth
Starters - Garland, Mitchell, Merrill, Giannis, Allen
Rotation - Ball, Anthony, Porter, Wade, Nance
Bench - Prince, Thanasis, plus 2 FA they add to get to 14 required
If that team is healthy in they playoffs they'd cruise through the east and have an excellent chance of beating whichever team survived the western gauntlet.
Is Mobley with Hunter and a young guy Tyson enough for Giannis, I have no idea, but Mobley is the real deal so it might be. Bucks wouldn't full on tank so the fact they don't own their draft picks is less an issue. I feel like they'd probably want a 1st and the Nets would need something to take on Strus, but that is a framework that could actually work.