I think there next to no chance this deal happens. Too complex, but for the sake of message board discussions, here are my thoughts. Simmons is a really really good player. He is top of the scale in really everything except shooting, which certainly is tremendously important. He needs out of Philly. Its not going to work there. However, I think he needs to go to a non pressure cooker. Boston is a bad spot for a guy who might need to fail quietly as he builds himself back up . I saw Minnesota was hot for him and I thought that is the perfect type of landing spot. You also have the problem that one of these teams in the Celtics and Philly trade is going to end up with egg on their face. Best if its not a conference long time rival that you are going to have to play multiple times per season.
Simmons on his tour back to recovery needs an experienced coach who knows how to use him, and not put him in spots where his glaring weakness is going to be front and center. I know he just hit a milestone, but I have been preaching for years that Doc is a terrible coach. He gets by on personality, but he stinks in game day coaching. In the same regard at this point, Ime is not ready for the circus that comes with Simmons. He has had three post game media sessions that may or may not have been too revealing(nuking the team for effort after second game of season, questions Jaylen's focus as he was a few days removed from COVID, and pointing the finger at Marcus after that brutal sequence...out of a timeout..when you every chance in the world to make clear what you wanted). I am not even certain he is ready to be an NBA head coach, let alone tasked with keeping his emotions in check when Simmons is passing up layups in tight games.
I am nearing a no return point with Marcus. I believe the contract they gave him was to make him a nice trade chip. Who knows where they are in 2 plus months when he is trade eligible, but right now, I would have no problem moving him. For those that say it will be tough losing him because of his defense...Simmons is a better defender than him. I have no idea if Jaylen and Tatum get along, but they both need the ball and are both wing players. I would guess that Simmons would work better with Tatum. however if you are committed to trading Jaylen, I think you may want to shop around to see if you can find a non distressed asset.
If it had to happen, my guess is something like Simmons/Thybulle or Simmons/Maxey for Smart/Timelord/Nesmith and 2 forst round picks. I would love Curry in the deal but I think its too much. Timelord also doesnt fit playing alongside Embiid, so my guess is a third team would be needed, with more bodies in play including Horford, Schroeder, Romeo, Kanter(is he still alive) and Richardson.