Make an agreement with Cleveland for Rondo, buy him out and take a pick swap for 2019 and a 2017 2nd. Call up Keith Benson, send Cannan down, call up McCallum for a 10 day contract to cover. Juggle D-League until you find someone clearly better than Cannan, and right now there are about 3-4 guards that make a good case for it.
Hire a dedicated shooting coach immediately. There are only a handful of good ones available at this point of the year, and don't hire some youtuber like Collin Castellaw because he has a lot of his own bad habits that translate to injury. Hire someone that has a pro-game knowledge of shot mechanics.
Groom Valentine as a combo. I've said it a million times, what does it hurt once more?
There ya go, now you might have a shot at the second round and could draw a decent FA in the offseason. Still, not a title contender, but if they're going to sit on their hands, may as well develop the players you have and let Wade die in peace before he walks or sticks the team for his ridiculous contract.