For Olimar:
I had trouble with this MU before, but if you look for P1's post about it in the MU thread it really helps. Basically, you have to be aggro in the first part of the match to get a significant lead. It's hard for us to approach Olimar because of his pikmin (our bananas are linear and so are his pikmin), however, it's difficult for him to approach us (lack of range and slow movement). If you pretty much make him approach you, it won't be good for him. Olimar is terrible with pressure, so once he approaches and you get in, STAY IN. Even though it's hard to use bananas in this MU you still need them. I saw you tried to approach way to much without them. Try coming in diagonally (i.e. short-hopped naner throws). Also you gotta knock those pikmin off, again I recommend what P1 said, use short hopped nairs (you can z-drop nanas and nair to recatch them). You either have to be all over him or nowhere near him, in between doesn't work.
For Sonic:
This match-up is one of those that you lose the first time, look back at it later thinking "how the **** did I lose that?", and then learn it. Sonic is really good at punishing mistakes and seeing the Olimar match you played, you probably approached a lot. That's pretty much the only way Sonic can win, he has to punish your approaches. However, nanas beat everything he has. He has no projectile, so literally wait for him to approach and punish with nanas. He will be very tricky in trying to bait some obvious move. So long as you don't throw out random air dodges and make careless mistakes, it should be an easy MU for you. Oh yea, remember that he won't trip in spin dash unless you hit him with the banana. If it's on the ground already, he'll just run right over it.