Forgot trading Smart, the C's could "easily" acquire Covington without including him. Having both Smart and Covington (with all other core pieces) sounds like a pretty nice defensive squad to me.
Now it all depends on what Minny is looking for, but this could be a time to consolidate some chips (which the C's will need to do before next year anyway, not enough room for the 3 main rookies from this year + 3 rookies next year + Waters). Trades for Covington like the following work in the trade machine:
Poirer+Langford+Edwards/Ojeleye
Poirer+G. Williams+Ojeleye
Plus maybe throw in 1-2 picks from this years draft (are we really expecting much out of the Bucks and Celtics picks?).
I'm sure someone will argue not to trade the young guys, haven't even seen what Romeo can do, definitely don't include picks, yada, yada, yada, but you have to give to get.
Romeo might never see the light of day playing behind Smart, Brown, Hayward, Covington, Tatum at the wings.
Williams/Ojeleye would lose time to Covington.
And the C's might have to waste a pick on another Yabu-like-stash because they won't have room on the roster next year.
With Covington you also get a guy with a medium sized contract for the next 2 years, making other trades much more feasible.
Also a chance to promote Waters to the main roster.
3-for-1 for a player on Covington's level is always tough, but could also make it a three-way to spread it out a little. Just spitballing something that works (not thinking about why the other teams would actually do it, just how it's possible):
Covington to Boston, Bjelica and Edwards to Minny, Langford and Poirier to Sacramento.
Of course, this all assumes at least one of Langford, G. Williams, Edwards having some value across the league.
Just spitballing, not really analyzing too much. But it seems possible to me to keep the core and add Covington by trading some rookies and picks (if Minny values that).
Or maybe Boston helps facilitate a D'Angelo Russell trade , with Boston sending picks to GS instead of Minny.