My approach against Cleveland would be to attack them with lots of:
a) Speed
b) Ball movement
c) Shooting
They have a roster full of crappy defensive players (Thompson, Love, Irving, Mo Williams, etc) combined with a Lebron James who plays defense more or less when he feels like it. Mozgov and Shumpert are basically the only consistent defensive presence the team has...and with all the huge contracts they're throwing out, that roster will be staying the same for a long time.
I say if you want to beat the Cavs you do it by forcing their poor perimeter defenders to run around chasing the ball - lots of speed, lots of ball movement, constantly swinging the ball around the court.
On the front court, keep at least 4 outside threats on the court at all times - force their bigs (Love and Mozgov) to leave the paint and to go after shooters, which then opens up opportunities for offensive rebounds.
A relatively quick lineup like this also helps us make things hard for them on defense, because we'll have the speed/mobility/versatility to stick with the ball and switch on the P&R.
I'm thinking...
PG - Terry Rozier
SG - Marcus Smart
SF - Jonas Jerebko
PF - Amir Johnson
C - Tyler Zeller
Defense
The key part here is the three headed monster of Smart/Jerebko/Johnson - all three of those guys can defend their own position, one position above, or one position below. Smart can cover PG/SG/SF, Jerebko can cover SG/SF/PF and Johnson can cover SF/PF/C. Those three guys form a versatile defensive trio who can cover the P&R as well as any probably trio in the league.
Zeller has the mobility / size combination to defend both frontcourt positions, while Rozier has the speed and length to defend both guard positions without much trouble.
Offense
Rozier, Smart, Jerebko and Johnson can all step out and hit the three, while Zeller has developed into a dangerous midrange shooter. Everybody on this roster can hit jumpers, so it forces everybody on the Cleveland team (bigs and perimeters players alike) to respect the shot.
At the same time Rozier, Jerebko, Johnson and Zeller can all get to (and score at) the basket, so it makes it Cavs can't afford to defend the perimeter too closely.
Everybody (bar Jerebko) here is a capable passer too, so you should end up with plenty of ball movement.
Finally this is an extremely agile/athletic lineup, so plenty of movement.
I think this would prove to be a tough lineup to defend.
Rebounding
Zeller, Johnson and Jerebko are all solid rebounding bigs (9, 8 and 8 rebounds Per 36 respectively) while Rozier and Smart are both very good rebounders at the guard positions. None of these guys are dominant rebounders on their own, but I think as a team this team will grab it's share of rebounds.