-Fox's Jab causes tumble stun at around 130-170% (fox 130%, great for chaining into smashes, marth 150%)
-Fox's Jab can be combo'd into Usmashes or any other fast attack even without tumble at around 80% up
-Without DI fox's jab launches the opponent diagonally in the direction of the jab, but most players I've played tend to DI in to jabs, causing them to go straight up (VERY common when playing cpus). So if you're getting jabbed make sure to DI out to avoid potential risk of getting comboed. =]
-Fire fox and Illusion have different landing delays (Illusion is longer by FAR)
-Fire foxing into the floor does not affect its landing delay
-If you fire fox sideways from the ground the tumbling animation that results at the end is part of the post attack delay (Which is VERY LONG), but if you fire fox in the air toward's the ground, the resulting tumble is part of the special fall and as a result immediately gets canceled if you hit the floor. This shortened landing delay also occurs if you fire fox between platforms because you leave the floor. So be in the air if you're going to use an offensive fire fox.
-Fire fox stuns your opponents for a long time.
-You can fire fox at around 1-10 degrees (sorry for not knowing exact angles) into the ground without triggering the floor slam effect.
-Sound effects for attacks change as they get stale
-To maximize horizontal distance with fire fox aim 22.5 degrees diagonally and mash forward. It's about 1-2 character spaces farther than aiming straight forward or 45 degrees up
-fire fox seems to grab the edge before the end of the animation if you fire horizontally at a short distance away, but I'm not sure and someone else with AR should test it. Fire fox DOES, however, grab the edge early if you aim at it from above the ledge, and you can also grab the ledge backwards during the tumble animation at the start of the special fall
-the landing delay for air dodging with fox (yes, this includes landing delay from wavedashing) is longer than the normal landing delay of just jumping and doing nothing (i'm sure this applies to every other character as well)
-Marth's dolphin slash goes farther left if you mash forward at the start-up of the attack by about 1 character size, at the cost of less height.
-Some air attacks will allow you to land normally if you hit the floor during the last few delay frames of the attack, like Marth's short hop nair, meaning some attacks don't have to be L canceled.
-The stun time is shorter at higher percentages if your shield breaks, which is really weird, i would think that it would be longer
-Fox's level 9 computer AI will always use reflector at a set time after he tosses you upward, even if you land on a platform above you.
-Reflector does not reflect at the one attack frame that occurs at the start of the attack (needs confirmation)
Most of this data was gathered from training mode against fox and marth. Percent damage info is probably somewhat inaccurate since i was gathering this info to increase my chances against beating a friend who main's marth. Anyway, Enjoy. Sorry if any of these are reposts.