Ok, as there are 5 pages, I'm skipping through it and when I saw how Gazelle said olimar's Dsmash has a sweet spot and it may only work on large enemies, Gazelle is definately wrong.. It works on small people like G&W and pikachu also, as I have done this.
Just throwing it out there.
As far as other things..
Pit Vid 2-
Nice on the whole, however you seemed to attack where most people would go to usually. I did not look up the tournament rules, but if it's a three match tourny or however it was.. you should try to get in the habit of teaching people where to go for the next match. So basically you want to hit the obvious spot first.. next match you should be hitting the best route for escape.
As in, first match, hit him on the ground, next is the fair when he is not there.
Unless, of course, you are just used to Marth's range and you attempted to tip him with your sword.
I looked at more of your vids via youtube and saw some fights where you missed the ub+b and should have got on. Of course, you don't always need to get on and you can die, as everyone can do once in a while.. but times where a Marth jumps in range to hit YOU off the ledge, you can UP+B through him to the ledge.
Remember the tether grab has about a.. 190* angle of hitting the ledge. With the extra ten being above the ledge and pulling you onto the ground in a standing position. (Which can be used to smash, tilt, run, whatever.
So generally, Uair, or F+B purple, or fast up+b when in range (Immediately is immediate).