I'm a big De'Aaron fan. I was hoping he'd take another leap forward this season and vault into all-star status while powering the Kings to a playoff berth. I still hope he breaks out of the slump he's in and that happens.
But as I've said, if the Kings were to trade for Simmons, Fox is the piece to send to Philly. First because Morey won't take a package centered around Buddy and Bagley. But also because Fox and Simmons aren't a good fit. Both are ball dominant players who don't space the floor. Fox is at least a threat from outside while Simmons is a non shooter, but either way even with good shooters at the other wing/guard spots it wouldn't work, especially with Holmes at center. And Richaun has been fantastic so far this year.
Simmons is tough to build around, but the Kings have a pretty good roster to match with his skill set. Mitchell and Hali are both good shooters and CAN run the offense/function as secondary ball handlers, but don't NEED the ball to be effective. Barnes is a switchable 3/4 who can also space the floor and Holmes is the rim running lob threat that is great in the pick and roll.
Holmes
Barnes
Simmons
Haliburton
Mitchell
is a playoff caliber starting five and Hield & Davis provide even more shooting/scoring off the bench. Harkless can spell Barnes and Simmons, and Len/Thompson provide the big body on nights when the Kings play teams with bigger/stronger centers.
You could even finish games against smaller teams/teams that move to a small ball lineup with:
Simmons
Barnes
Hield
Haliburton
Mitchell
Fox is probably the best player Morey could get for Simmons now and he'd be able to save face with that deal. But since the Kings aren't playing Bagley and Simmons' salary is higher than Fox, I'd throw in Marvin and ask for Thybulle or Maxey, preferably Thybulle.
Again, I don't necessarily want to see Fox moved. He's been the biggest bright spot for the Kings for years and actually wants to be in Sacramento. But Simmons makes this team playoff caliber and all of the starting lineup except Barnes would be locked in for 3 years or more. It's definitely worth considering.