I should of phrased those better, and I hardly wrote my best. I will adjust those a bit, but teleport is only a reliable escape option when combined with LC or when the opponent is experiencing major lag. Plus, it is almost always punishable by a dash attack or grab. It isn't the safest escape option, but it is one, a the very least it is an okay mix-up.
I tried to sound optimal with disable, but it isn't the greatest of moves. It is better then his smash attacks (fsmash 3 frames slower, Dsmash 5 frames slower and Usmash is actually 7 frames faster) and the big difference is in ending lag as disable has 48 FAF, Dsmash has 44 FAF Usmash has 74 and Fsmash has 53. So Disable is a good option, but it is about as good as his smashes. as it is slower start-up then Usmash but more endlag and faster startup then Dsmash but more endlag. So Disable is good, but only as an addition to smash attacks as it has other weaknesses as well, like low shield KB and easily beatable by almost any tilt. I will definitely change Disable and make it sound better, I will also mention it's range, but it is about as good as his smash attacks and is probably best as a mix-up.
Edit: As the Metagame for Mewtwo is still so new, I will add Disable and Teleport to the discussion topics and note the aspects in contest. The metagame is so new that I could very well be wrong, so I want to cover all the bases and flesh it out a bit more.