So we were right and then second-guessed ourselves...good to know, and thanks.

Can someone like Nul be knocked back with Pulse Wave if it hits him with doubles?

Personally, with the release of Pacific Rim figs and movies, I find it hard to believe we haven't had KB of COLOSSALs by other COLOSSALs yet. Same with them knocking back giants and giants being able to KB other giants. The movie had COLOSSALs flying everywhere.

Yes. Both Charge and the combat abilities he has due to will be ignored during Pulse Wave, so nothing would prevent it.

Do you mean "haven't had a rules change to allow" KB of giants/colossi by other giants/colossi? I wouldn't expect that based on the movie: there's always been visuals of giants and colossi being knocked back in the source material, but that hasn't caused the rule to change yet.