In 2016, it would've been a nice deal for the Bulls; in 2017, I hate it.
LaVine's a better shooter from range the Rose ever was, but the parallels of a young, athleticism-dependent, emerging-star guard felled by ACL tear are not encouraging. Dunn is a defensive monster, but otherwise terrible—and old, for a player with one season in the league—on a team that really needs a scoring PG (or needs to dump Hoiberg). And not receiving any additional or future picks back—they essentially just traded up, from 16 to 7, to draft a non-star rotation player—for a consensus top-10 two-way NBA talent is just garbage, even considering they need to be garbage for a few years to really rebuild. The cherry on top is that they sold their second-rounder to GSW, and in the aftermath essentially admitted that (a) they don't understand NBA roster rules and (b) did both a terrible and shockingly-cursory job scouting the draft. The front office is in omnishambles, and I have no faith the Bulls will successfully execute a rebuild until John Paxson and Gar Forman are kicked to the curb—which probably won't happen in Jerry Reinsdorf's lifetime.
He is just a completely different kind of player though. I don't see the need to make the comparison with Rose. Rose was absolutely dependent on his athleticism because his game was attack the basket or pull up jumpers. He could not play off the ball because his shooting was subpar. Lavine is the type of player that doesn't demand the ball and can extend the defense out to the 3 point line which is the most important thing in todays game so your slashers/PG can operate in more space. There is no question the ACL tear is concerning but as he gains experience I am anticipating his shooting continues to improve. He is basically the prototypical 2 guard in todays NBA. Potentially great shooter who can slash off the ball and still playmake on occasion to give your guard a rest.
I won't pretend like I've seen Dunn play a lot but in the few times I came away impressed. I don't think his shooting numbers last year are indicative of the type of shot he will have moving forward. He will never be a gerat shooter or anything but not anyone you can just deliberately play off of. His defense like you mentioned is elite. His playmaking is very good and in the opportunities he had to play with teh first unit last year he excelled. I think he can be an excellent piece moving forward.
I have no clue about the kid drafted.
Either way - I think its a misnomer that a rebuild has to start with trading for the youngest players possible or picks. If Lavine has a great year next year you can convert him into 2-3 pieces. Likewise with Dunn. Then you have a nice pyramid scheme until you get the players you want. The best thing Chicago can do is just play up tempo and inflate the stats of their players.