Really good fox.
I took a close look at the Marth game and here are some suggestions:
1. Start of strong. Marth freakin owned you in the beginning and was leading like 50% to none. You caught up, but you gave him momentum to start the game. Once you start landing the combos you want to, you gain confidence in your movements and that's a significant factor in the game. (A little psychology thing there) It feels better to start off with a lead right?
2. Be consistent! I saw bursts of awesomeness and fail during the match. At certain points you make these mistakes (like when teching you made it easy for him to land a hit on you right after) but then at other points you come out and land a really sweet combo to either kill him or send him flying far.
3. Don't be so agressive at the end! I saw that after you lost your 2nd to last stock, you flew and attacked Marth like crazy! That wasn't the same speed as you played before! I saw that you made hasty moves which led to Marth calmly controlling and manipulating your attacks. Play it smart at the end instead of making hasty decisions.
All in all- your Fox is amazing, but still has room for improvement!
I shouldn't be giving you criticism since you're like 10x better than me, but I hope this helps