I think, as Wakato copies with a feat, he should be able to copy Mizuki. There are no abilities that negate feats, so there should be no problem with it.
Also, before you make your 3rd picks, please look at the following:
As you might have noticed, there are several players that are unable to spend all of their points in the remaining picking round. As our original intention was to give everyone the same team strenght, I thought about giving everyone an eight character. That characters total would be equal to the points the player has left.
If the player has no points left, the character has a total of 1.
Also, the character is allowed to have one feat (I would make a list to choose from).
The character is not stuck at that level though, everytime his team wins 1 point can be assigned to a chosen stat, if the character himself won a match, one more point can be distributed.
However there is a limitation in how much points can be distributed at max. It's clearly unreasonable to say that a low tier character (and afterall it is one, as you pay near to nothing for him) can be stronger than Sanada etc., yet it is also illogical to say that your character can't grow at all once a certain points is reached. That means there need to be a number of levels for the character, either 3 (high, mid, low tier) or 4 (add pro). However, to raise to a new level, a certain number of wins or something is needed.
This is only an idea, so please tell me you thoughts about it.