Well for Anti Ataxx, there would have to be some more special rules - otherwise at the end of the game, if I had the last move, I wouldn't just "clone" a piece to take the last spot, but I would jump - making my opponent take the next shot. (And if he was smart, he would do the same) - making an endless loop of each player making the opponent take the last/next move. Then would the rule be capturing the most, or any piece? If so, on my first piece, i would jump out in the middle to make my opponent capture it, and then try to do the same with my 2nd piece, and let the game end after 4 moves. Maybe I'm not playing it correctly in my head - but someone would need to sit down with a board and play some test games to see how anti-ataxx would work.
Ataxx 9x9 - no opinion.
Ataxx variant - clone orthogonally - jump L's or diagonally. Not sure what clone orthogonally - but can't we already jump L's or diagonally? I think i'm lost on this idea.