Marth: Yes, this match-up is hella tough! I mean, he has a super long range sword with a long range grab? Omg! It's too good to be true. It's NOT EASY to approach unless you bait him or jump all the way over him for a back-air and then hopefully get something started. You have fireballs, but those can only do so much, especially against someone that knows how to maneuver their way around them fairly easy. Remember, when you're against a Marth that f-airs way too **** much but it actually works and you can't get in, that's when you crouch cancel --> down smash. It works, just don't do it TOO MUCH. It'll become predictable and they'll get free percentage on you. Also, remember, when they up-b and you mess up and they end up hitting you, you can always crouch cancel and retaliate with a down tilt. Hey, it's percentage right? Food for thought.
Falco: Ok, A2ZOMG is right about this....maybe! I don't believe it's his worst match-up but it's at least in his top 3 worst match-ups for sure. You have the chain throws to (insert move here) and you also have the cape, which is good. I mean, you can always mind game by caping them one stock so next stock they'll expect the cape and then switch it up. Falco's not TOO TOUGH to edgeguard. You just have to know what you're doing against that particular player. About the lasers, SPAM YOUR CAPE! And when they get into range for attacking you, defend yourself! If a good falco puts shield pressure on you, just roll away at the right time or else you'll get punished or nair them if you can catch them off guard. Falco is **** hard you guys, trust me. I played Mango's Falco in friendlies, but I beat it for the most part consistently. So, it's not impossible =P
Samus: She's actually not TOO TOUGH. I mean, HugS is the only samus that has beaten my in tourney. I've beat ycz7 and death(I think that's his name). Mario can freakin' duck under the missiles, I mean come on ;D And cape them of course. When it comes to edgeguarding, just f-smash(aim it downwards) or cape just to get more damage. Samus is fairly easy to approach. It's not a Marth or Falco, so you're good.
But yes, grabbing any good player is very difficult. Catch them off guard! Do something unexpected! Switch it up! Trust me, it'll work (: I got a lot of grabs on Lucky's(Mango's former partner) Fox, so you guys can get a lot of grabs on anyone! Don't give up!