I honestly enjoy the fox MU, and he definitely isn't our worst, yoshi is. But fox is quick, but we have solid beef against him.
-His jab combo setups can be rested. If he tries doing that double jab stuff, just soam rest, and it will hit mid combo. If you dont want to risk that, it's an easy smash di away. And since these are his most reliable kill combos, that is suddenly taken away from him.
-Fox has issues approaching puff. the best fox approaches in neutral is a sh aerial, grab, or dash attack. We can beat out all these approaches with out sh aerials, and his dash attack and grab are beaten if we sh aerial. He can't approach all too well, so we get to be aggressive. His lasers you mentioned are an issue, but we can easily duck them and stall the match. He doesnt get all too much out of lasers honestly.
-Fox has kill power, but no setups against puff. We normally avoid being above characters in any way, so uair doesnt get all too many chances, unless we somehow miss a tech on a uthrow into a platform.
-Fox's recovery is super gimpable. Nair beats his phantasm and fire fox. If fox is offstage above the stage ledge, follow him so you can get the phantasm, if he's below the stage ledge dont expect a phantasm, and go for the dair spike. If you FF dair, and hit all hits except the last one, you get a semi spike. Dair beats fire fox, and can get you the win often. Fox is pretty easy to gimp.
-Helicopter kick is a good anti-air, but has issues if it misses, due to end lag, it can be good, but if we can bait it, it can lead to a good punish string. BE CAREFUL