here's a vod of me doing good https://youtu.be/usGgswFPDzw?t=2705 (6-0 in grands)
- fullhop strong bair should be a goto option at any percent. It doesn't matter if they cc or shield it.
- luigis will try to catch your jump out of shield with dsmash.
- fullhopping (sort of in place) while luigi is really far away is good. He can't cover diagonally in front of him in the air kinda like sopo.
- when you get luigi offstage try to shinespike. or if you think they'll airdodge to stage, stand there and uptilt or upsmash (i find shine to not usually work in this situation)
- if you read they're going to double jump fireball, you can fullhop over it and shine spike them usually
- soft shield to avoid misfires
- low percent: fullhop or short hop drill -> shine stuff is good
- off shines you can fast wavedash fast nair or dash into jc grab (i dont see other foxes do these much)
- if they down b while coming down, shield it, then wavedash out of shield punish (upsmash, grab, uptilt depending)
- shark with uptilt good, though it may trade
- you can also shark with run past flying fullhop backair (you want to try to hit his backside while rising and you're drifting away. luigi comes down with nair or dair and this should dodge either one).
- high recoveries generally very good vs luigi
- When luigi is at high percent they tend to ledgedash into shield. You can kinda read this with a grab but it's sorta risky for low reward. But there's not much else you can do really.
- Backthrowing luigi offstage is always pretty good
- On tri-plat stages at low percent upthrow under top plat sometimes forces them to tech on the top plat. This is a great way to try to set up upairs against them.