So this would be heavily inspired by the actual RIFTS setting, I gather. Mayhaps less sci-fi because there you got power armors as the "norm" for more civilized factions and also magic was strong enough to easily keep pace with the highest tech.

Alright, my initial feeling was that you wanted to make an ISOT setting where everyone nation just freshly drops in this world, or perhaps got here relatively recently. But instead you want a massively multiversal setting where elves from a fantasy universe have to find their place alongside sci-fi robots and other races within the same country.