I was going to ask you how hard it was to move to the US, but having a US dad would've made it easier.
Bet it would've been a big culture change.
On stright pull ARs, I don't recall ever seeing one over here or hearing of them.
I've been on a few Aussie hunting/gun forums also, and never seen them mentioned either.
But on shootforum.com a UK based shooting forum, they are mentioned a bit and seem to be popular.