Awesome another kiwi on here. Cool car i have never seen a hatch before i didnt know there were any in NZ. I would be looking to put an EJ22 in there, the FWD EJ gearbox would work but traction might be a problem. I would go 4WD and build a custom fuel tank or modify yours. Finding doors and front guards could be hard, it took me a long time to find decent guards for my brumby and one of them has a small patch of rust at the bottom.
I am wrecking a seriously rusty brumby and have a few spares including a good ea81 and 4 speed dr box.