Yeah if you want to take this seriously (and I know most of you have a hard time doing so) you should just camp. Get a lead (which isn't all that hard, really) and just camp him like nothing else.
If he jumps, you land and grab his landing.
If he remains grounded, you can safely dair him.
This may look kind of black-and-white (it is, teehee) but in the end the only tool he has against us is uair, uair = air = ololol he's dead. He's just a terrible character who happens to have grab release gimmicks on us, but with a slow and terrible, terrible grab like his, you should never get grabbed in the first place.
If you dò manage to get grabbed, shrug off the 25% damage which won't kill (after all, you won't ever get to kill percentages in this MU) and continue to take advantage of a silly MU.
Seriously though, play a few friendlies against good Ganons, understand why this MU is impossible for them and you'll have all the experience you need to never lose in tournament sets against Ganondorf.