It's not even known if it will be a mixture of tracked/wheeled yet. If there is one thing the ADF/DMO is good at, it's friggin around.
Army will be watching US decisions very closely with the GCV, but should that fall through, some of the possible replacements would be:
Wheeled for Cav, tracked for infantry.
It will be interesting to see if the Marine Corps ACV gets a buy as well for 2 RAR/ARG.