I came over on a green card, wife is American.
But the first company I worked for flying a 212 and 412 in 2016 also had an Aussie flying their 802 Air Tractor on an E3, and last season they used an Aussie on their 212 contract on an E3.
So it’s doable you just have to find the right companies that understand what the E3 visa is and the fact it’s not a sponsored visa at all.
For anyone thinking of doing the E3 thing, it’s not like the regional airlines where they will convert your license for you. You will have to be ready made with FAA tickets in hand for rotary jobs.
Good luck. How’s the time to be speaking with fire companies as it’s this time of year they’re locking down all their pilots for next season.