The only moves you can't do to a low percent fox are jab, poorly spaced tilts, and a bad dash attack. Any of those things "can" be done well, like spacing the dash attack far behind them or dashbacking/shielding out of the jab, but that overcomplicates things.
If you wanna keep it simple in neutral, I'd aim for uptilt (which will convert at real low % to down tilt or down smash with almost universal success - one of my favorite options v more aggressive foxes is to run away from them, turn around uptilt as they approach you toward the ledge, downsmash them off the stage into cookie cutter edge guards. Depends on fox.) or intelligently placed and spaced f tilts.
If they're camping you, they'll probably be at one side of the stage, which means your greatest advantage is positional. If you put yourself at a healthily close proximity to the ledge with the fox between you, lasers make them vulnerable, and their options are to jump over you, go to ledge, or try and run/attack through you. You can reactively hold that space by nairing/fairing/upairing their platform jump or wavedash back ftilt/downtilt their forward approach.
Basically, If you don't overextend or throw out unsafe neutral options, your presence is a zoning threat to any fox. Just don't be too fast to put yourself into move lag and be sure to hold your safe position. Stay outside grab and shine range, try and reactively shield/counterattack/bail if they rush you, don't use low impact moves at low percents, keep close to them if they're lasering, and the fox neutral suddenly seems relatively even.