Few thoughts I'll post them as I watch:
So yea with the grab game you're caught in between because you're fthrow/dthrow tech chasing but you're not doing it on reaction and guessing a lot so you end up playing a high risk high reward game that ultimately imo, will always end up catching up to marth if he tries to play like this long term. You either have to tech chase honestly or use up throw but really up throw is good. Sidenote, recently I've gotten frustrated with fthrow/dthrow tech chase stuff because people are getting too good at just sliding themselves onto the ledge and it seems like there's a pretty big window/space/area for them to do that. Really annoying to get nothing off grab. Just a little tangent, but yea, up throw is good.
Don't up throw to top platform and try to tech chase with nair. Super easy to CC into shield or moves in order to beat it, and now you're out of position if they shield drop or kinda do whatever they want. You either have to recognize that at that position and percent up throw isn't going to yield anything or, if you can get there in time you need to fair/uair/bair depending on where they tech in relation to you. If you have a lot of time, go for dair. :D
You're getting beat by high side B recovery quite a bit. High side B recovery is super obvious on every space animal so instead of walking too close to the ledge too soon and then being force to do things like bair him back into the middle of the stage or get nothing at all if he edge cancels, stay back for a second and then jump fair the high side b. Keep pushing him off stage as he'll probably then side b again immediately and you just jab or do whatever at that point.
You're missing tippers on your bairs quite a bit. Some people don't realize how stupidly high above marth's head this hitbox reaches.
Smash DI lasers away to get out of laser fsmash.
If you're going to be aggressive in pursuing Falco when he's goes to top platform, you've gotta be sure that you're going to hit him. You can't afford to just whiff bairs underneath him entirely or whiff them on his shield. Marth can combo at full hop height but he's in no position to bait or exchange with an OOS opponent from that position.
http://www.youtube.com/watch?v=yl_zFYDq5Pw This set always struck me as a good example of swinging to HIT on top platform Falco. Especially the dreamland matches. Admittedly tho, this Falco is really obvious about where he's going and way less tricky than someone like Westballz, still tho, concept applies.
Overall your play looks a bit janky and what I like to term "unorganized" (probably the biggest criticism I have of my own play as well). Basically when you're unorganized you kinda roam around unsafely and go for random hits instead of being disciplined and finding the type of hits (like grab) that will start efficient big damage/stock taking combos for you. Random bairs at 0 will not do that. I think basically your spacing is being compromised because you're not powershielding at all. If you can powershield consistently you will establish a presence on the ground and not always be on the outside looking in trying to poke Falco with random stuff while he dominates the stage. As a result, you'll get more grabs and more meaningful hits, and less random pokes or hits that get CC'd into Falco combos.
Edgeguarding also looks like it has much room for improvement. I think you're a bit passive. Spacies 2 good to do it all on reaction anymore. Not saying you need to blind guess what he's going to do, but just realize that at certain knockbacks they favor certain recovery options universally and there are tons of tip offs in their behavior during recovery that will indicate what they are probably going for. Basically my outlook to edgeguarding them now is to get myself into as generally option cover-y a position as I can at the start and as I watch them fall and wait for a DJ I start to develop some sort of idea of what they are going to do and prioritize things that are harder to cover on reaction. This stuff just takes experience (neverending, ongoing process really) and will allow you to be more aggressive in your edgeguards.
Really nice Marth. Stylistically reminds me of my own a lot, actually.