I tried this moveset out, and I think it is really good, though I have a few points of criticism.
While Mephiles' standard attacks and smashes are good as they are, his specials feel kind of... unfinished.
For example, his neutral special. I really don't know how to use it, and what exactly it is supposed to to. The only thing I notice, is that enemies are flipped when they don't face Mephiles' direction, and are frozen for a few seconds.
His up special is really weak. It is almost impossible to hit an enemy with it, and it doesn't go high enough, to make a (in my opinion) good recovery. Also, I think you should be able to angle Mephiles while he is using it.
Down Special is way to slow to be useful, and it's power isn't worth using it. You should either speed it up, or make it more powerful.
Side special is actually OK as it is.
So... these are my thoughts. I hope they help you to enhance this moveset.