You don't need combos against G&W. You only have to hit him 4 or 5 times to kill him.
That being said, just grab him or hit him out of everything with up-airs. Ganon destroys G&W without mercy.
Edit: One thing I noticed was that, in that vid, you d-tilted and attempted to follow with f-air. Too slow. You should follow with up-air, since it's both faster and safer due to longer range. You wouldn't have gotten 9'd with an up-air. You should also be camping him with b-airs, since you have the better range, power, and priority. He can only approach with f-air, so just wait for it and space the b-air, and you can even go through his shield with it easily. With that G&W being so offensive, a Ganon should be able to destroy him just by abusing range.
