I like where your head is at, but these are the potential problems I see.
1. It's a very late game play. Disco costs six, flamenco costs five. That's turn 11.
2. At that point, all Lanes are full and since none of them are amphibious, you won't be able to play grave digger without one of them being removed.
3. Placement is tricky. Remember that disco will recreate it's two minions when it comes out from that gravestone.... Not super huge if you can find a way to get Gravedigger in there, but just remember you'll want flamenco in lane 4, which can be messed up based on the plants on the board. If lane four has a plant that will kill flamenco, the plan is shot.
4. Removal, you'll need it. As a matter of fact, when running a long game strat like this, it's better to run a control deck. (And there are more effective long game stats for the cost)
5. Card draw. You need it.