I don't think Hayward comes back this year and even if he does, he isn't going to be the Hayward that signed this summer.
It's not an injury that's very common, so it's hard to compare outcomes. Paul George was similarly injured before the 2015 season; he played six games at the end of the season, to no great effect. He then played 81 games the following year and made the all-star team.
Obviously Hayward is not George, and there are differences between how fast an individual heals, how bad the injury is, how good the rehab is, how devoted they are to it, etc., etc. It sounds like Hayward could be back this season, but you're probably right that he won't match his pre-injury play this year.
Smart is a bench player. A good one, but still a bench player and the team has still gone 18-14 since the 22-4 start, much of that with Smart playing.
Smart has consistently averaged the fifth-most minutes on the team. Obviously Stevens likes what he brings. So - he's literally a bench player, but he plays starter's minutes. On the other hand, he did not play well for an extended period before he hurt himself (reportedly, he was mad at himself for his play). The turnovers, especially, have been alarming.
Monroe is a nice player, but he isn't shifting the wins more than a game or two. Boston didn't dramatically overhaul its team and make itself significantly better. Not like Cleveland.
If Monroe shifted the wins by a game, that would be a big contribution! But likely it'll be more modest than that.
I've always felt that he was misused and underappreciated in his previous gigs. Stan VG's idea of playing him with Drummond in twin-towers lineups was refreshingly counter-conventional, but got mediocre results and took away some of his strengths.
Whether or not Cleveland made itself significantly better is an open question, I think. Addition by subtraction? They had Nance in at crunchtime last night, and he delivered; and it's hard to believe that Hill has lost his defensive mojo for good - probably that was more a function of the team he was on.
So far it looks like Thomas and Crowder have been re-born in their new surroundings.
I'm skeptical about the Lakers' recent personnel choices. The purpose, apparently, was to clear cap room - but are they really such a plum free agent destination this upcoming off-season? Off-loading Nance was a mistake, and IT's hip does not inspire confidence. They shed Clarkson's salary, but if a star or two don't want to play for them it doesn't amount to much. And their plan is to play both Ingram and Paul George together? Maybe, maybe not. At any rate, if I were George I'd consider my legacy and my chance at a ring.