Re: USA Visa
Sounds like they could only stay longer on one of those "critical business" work visas. You know, like kangaroo kontrol in Juneau. I heard the infestation is absolutely horrible, and none of the locals have any idea of how to katch them.
If you think it can't happen...when I was in grade school local shop, jokingly, wrote "alligators in basement" on their electric bill. For YEARS after that, the meter readers would not go into the basement unaccompanied to read the meter. Because it said right there "alligators in basement" and they knew that was an urban myth but IT SAID SO RIGHT THERE.
IIRC Americans are limited to two years in Oz even if they are there for critical employment so as you say, limits are not unusual. Still, sometimes it pays to contact the folks who are petty diplomats, and sometimes these things can be changed from "usual" to "a bit better". Now that overseas phone calls cost two cents a minute instead of five dollars...it doesn't hurt so much to ask.
But first I'd call around in Juneau to get the buzz about the 'roo infestation going.