Only the SE will be available December. At the Finnish Amiga demo the XE wouldn't work and no explanation was given (like the ROM wasn't updated or something). No timeline has been given for the XE so I'm not even considering buying one.
As for the AOS4 timeline, I don't have superior knowledge, merely superior ability to use logic. The only thing AOS4-related which was demonstrated was a really buggy 3.x/4 hybrid which ran on a friggin A4000. Assuming Hyperion is sane, if they had something better to demonstrate at the time they would have. Furthermore none of the Amiga partners have claimed to find a silver bullet to bypass the long and tedious process of porting an OS to a completely new platform which has a new interrupt controller, north bridge, sough bridge, memory controller, ISA/ABI, etc. The only thing they have done lately is brag that they finished exec. Well woop de do!
AOS4 isn't finished now, and even if it was it will take a long time before it's stable on new hardware, say 2004.
I don't have special knowledge, I can see the bloody forrest from the trees!