I'd try a 3-team deal with LAC-BOS-BKN and hope BOS gets Zubac from it. I think it'd have to be some 3-teamer because of LAC's cap situation too, Simons + picks for Zubac doesn't work on it's own, there'd have to be a few other players or salaries involved and BKN could help with that.
But the general framework, I'd absolutely be fine giving up Simons, 2 future first round picks, and some combination of Tillman/Baylor/2nd round picks to further facilitate and make possible. Obviously I'm not saying the last 3 are "valuable" pieces but just for potential salary-matching and/or further incentive for a certain team like BKN.
Ya, if the trade is done this season the LAC has to send out an additional salary like DJJ or Lopez because they are hard capped at the first apron and so only have 1.2 million in wiggle room.
If it waits until the offseason Boston could just take his into the Porzingis TPE because Simons will expire and open up enough room under their first apron to actually use the TPE.
As of now Boston can trade their 26' OR 27' firsts, but not both. They can also trade 31' OR 32' firsts, but not both. This is due to the Stepien rule, you can't be without a first rounder in two consecutive years and they've already traded 29'. So they can really only trade two first rounders as of right now.
They do have the 26' 2nd Best Of NOP/NYK/POR/MIN which right now seems very likely to be the Pelicans pick and almost certainly in the 31-35 range. They also have the 26' 2nd best of ORL/DET/MIL which with Giannis out and maybe on the trade block could also end up high in the 2nd round.