Before we get into why this works for all 3 teams I want to make clear that it's highly likely that Gary Trent declines his option, making his an expiring contract at the end of this season. He has outplayed the value of his deal and with the cap rising he'd be foolish not to. Now...

Why for NY? They give up a protected 25' first and two guys who are out of the rotation for a guy who can play big minutes and defends at a high enough level that Thibs will play him. Yes he's expiring but we get a good look to see if he fits while offloading the extra years of Fournier's deal so it's worth the price

Why for Toronto? They net a few draft picks and get a look at Reddish for Trent's expiring. While Trent is liked in Toronto the Raptors aren't contending this year and the option to bring him back is still there in the off-season should they choose to do so. My guess is Masai is gonna use this deadline/off-season to do some reshuffling to fit more around Pascal and Barnes

Why for the Lakers? They buy low on Reddish, hoping he fits the roster better than. Nunn has to this point. Based on reporting, there's clearly something they see fit wise with Bron and co. as they've made multiple attempts to acquire Reddish within the last 2 years