I face Fox a ton...and the fox I face is usually spot-dodge compulsive so it's a real pain...however:
If he jumps a lot, then one option is to let him come to you and go for a shield grab. The downside is that his shine can prevent that. Or, you can be agressive and fight his aerials with your nair. It can be tricky but it's possible to beat his shffl'd nairs with your own, you just have to time it right. I would say go for the second kick in the nair since it has an extended duration and you can space yourself better. If your aerials just whiff him enough for a split second stun, and he's relatively close to you, go in for a JC grab. Another option is dash dancing out of range of his aerials, since this can give you an opening for a grab if you catch him just as he lands. Again let him come to you, and use your grabs and tech chases to rack up damage.
About the throwing...logically he can only DI out of throws at mid to high percents, so you should be doing down throws early on. Tech chase with grabs too, not just stomps, and side b can be useful if you're careful with your predictions. Re-grab him after low % stomps/side-b's. If he fails a tech, go for a shffl'd knee or stomp. Down throw to knee-ing a failed tech could be the make or break moment for him losing a stock early, and you want him to.
By the time he reaches 85-90% you should be throwing up (if you didn't kill him already) and following with an fsmash (after an up throw at mid 90s-100) Guaranteed kill pretty much, and if he DI's away then run and grab him again. 110% and up you can do up-throw to knee as a finish.
If he's smash happy then punish/shield grab his missed smashes. I know for sure he loves that up-throw to upsmash/uair. To deal with it: at low percents, fast fall and tech roll away to avoid the upsmash. At higher percents, DI left or right, or jump to avoid the uair. Or both. If he threw you before you could DI fast enough, hold down and spam jump. Either you jump and he misses, or you get hit but DI down so you won't fly as high. Don't ever try to evade with spot dodge, it's too laggy for CF and you'll just get hit/grabbed again.
