Looking at the schedule I figure 14 wins and 10 losses, so I'd say 54-28. A couple of losses in either direction wouldn't be all that surprising.
I can actually see the Cavs going 22-5. I don't think they will, but their schedule is pretty weak. They have 13 road games and one long road streak, but the only teams with winning records they play on the road are OKC, Denver, Portland, Miami, LAC, and Philly (not exactly a whose who). At home they have Toronto and Washington twice each, Milwaukee, San Antonio, Philly, and New Orleans. I can absolutely see them winning the vast majority of those games as well as all of their other games. That said, while 22-5 is possible, I think they are much more likely to go 18-9, which puts them at 51-31.
Looking at their schedule, I think Toronto will lose between 8 and 10 games for a record ranging from 58-24 to 56-26, and thus think they will finish with the best record.
Washington has an incredibly difficult schedule. They will lose at least 10 more games, meaning they have no real chance to get the 3rd seed and could realistically fall out of the 4th seed. The only reason they won't is Milwaukee also has a pretty difficult schedule. I mean the Bucks have a long stretch to close the year where every 2 days they have a game in a different city starting at home against Atlanta March 17, then to Cleveland, then home (LAC), then to Chicago, then home (San An), then to LAC, then to San Fran, then to LAL (this one is back to back with the Warriors), then to Denver, then home for 2 games (Boston then BKN), then NY, then home (ORL), then Philly to close out the year. I mean that is an awful way to close the season for the Bucks.