With no keywords - can I make a themed Team with Mr. M. if the two other characters chare a keyword?

No, per the rules, all Characters must have the keyword at force Construction. Characters with no keywords always break theme.

Ridiculous Regeneration does not state the D6 cannot be re-rolled, so yes, Mxyz can replace the D6 during that power.

Versing this guy will make you want to leave the game. He's comic-accurate, but way too powerful for his cost. I call broken.

He doesn't have that many clicks, has no reducers, and really can't hurt people too badly directly.

If I swap his Myx die with one of the opponent's two D6 for an attack, can the new value be probbed? Say opponent rolls 6, 1 and I swap in a Myx 1 for 1, 1; will they be able to prob it or will the Myx 1 stay in play? Would their prob affect the Myx die and theirs, or just theirs?

Yes, Myx can replace a Die after a roll, and then have the Roll Prob Controlled. Nothing on Myx's card indicates that the new Die prevents PC from being activated, all he does is replace one die. Once its replaced, the game continues on as normal, except the roll result is different, and Players can PC it as they see fit normally.

oh maaan, Mr. Mxy is so annoying. I had to get him, after my buddy controlled the game to his advantage against me. Both offensively and defensively very powerful.

I'm still loving playing this guy.

Recently came up 1 on 1 vs a charcater with Invun. Thought I was stuck, until it was pointed out his special Pulsewave would still cancel opponents Indomitable, so they take Pushing Damage if given two tokens. Awesome.