I changed the siblings. It now is 1/round advantage with the same conditions. I also changed their Technique, though I'm still not perfectly happy with it (it's basically a different version of the Emperor's).
I changed the "if both creatures are allied" to "if both creatures are hostile to you" in the Gambler to draw attention to the fact that it can (and indeed is encouraged) to be used on hostiles. Technically this is also a slight buff in situations where there are two different groups of bad guys fighting you, but that fits the theme of The Gambler anyway.