Howard the Duck is not a mutant, he's an alien from the extradimensional planet of Duckworld...So he has no mutant powers to loose. His "abilities" are a dirty sense of humor and a mastery of Quack Fu.
QUUUUUAAAACCCCKKKK-FUUUU!
I hear Squirrel Girl is on the 198 list, at least, according to Wilkipedia, if you can trust them...
Now, if someone has two heads, and gets hit by Wanda's little trick, would they be two people with one head each or one person with one head? This storyline is so...difficult...
I guess you're right, I shouldn't blame Wanda, she can't help it, so I'll blame Pietro instead...