Hmm, both you and your friend's approach are really predictable. Your approach is just walking straight towards you opponent or jumping to attack him. If your opponent knows how to dash dance and wavedash around properly to bait your attacks, you would get destroyed.
What you did in between stocks doing dash dances and wavedashing around is what you should be doing to space and bait attacks from your opponent. It allows you to look for openings and avoid being hit.
Practice chaingrabbing a lvl 1 fox computer, because you have trouble regrabbing after you up throw a low percent. You need to finish off chaingrabs with f-smashes, or fair combos with the help of u-tilts.
At the beginning of every new stock for your opponent, you always go for that grab for a chaingrab, and miss a ton of grabs. You should know that you don't always have to go for a chaingrab at the beginning, you leave yourself open by missing all those grabs where you could have been comboed to death. Protecting yourself with fairs to get in grabs, tech chasing to grab, shield grabbing is sometimes better than just running around grabbing randomly.
When fox fthrows you, he regrabs you. You can buffer shield roll away, jump away and fair him, sidestep, and I think you can grab him too (not sure about this). Basically, you shouldn't get regrabbed like this.
Don't dash attack all the way into the middle of your blade into his shield, don't fsmash at the middle of your blade at his shield, you're asking to get grabbed, which is what happend to you. Space yourself, and for those situations, you could have just grabbed him instead.
When he grabs you, DI behind him, it makes it harder for him to do u-throw to uair, and then smash DI the uair.
Thats what I have to say for now, hope that helped.