The "you don't resurrect outside of Egypt" issues has a simple solution: Egypt in itself can expand, and thus colonies are part of Egypt and people there can resurrect as long as they die on *Egyptian soil. In fact, this could turn into an Evangelistic Imperialism, where Egypt must expand so that all people can resurrect.
This could have an interesting twist.
Soldiers need to be able to resurrect, so you can resurrect as long as the soil is made Egyptian (otherwise, who'd join the expansionist forces only to be render to oblivion?). That would be great for camaraderie, "Gotta conquer that down else Tommy isn't going to heaven!". The problem then is that you have to explain how a soul sort of hovers outside of oblivion, and why that only happens for soldiers. So no.
A better solution would be that dying in battle has sort of an Egyptian-Valhalla kind of deal. Sure, resurrect if you die on Egyptian soil, but die in glory in battle and you get ushered into heaven by divine beings and don't need no feather test against your soul. - Which would be great in terms of convincing ex-cons to become soldiers. The 'Penal Legion' could be a powerful force, moreso than most, because dying in battle is their ONLY way into heaven. I could dig that, especially paired with an idea of evangelical charity "We will improve your lot" that could help drive innovation.
The idea of the brutality of the Penal Legion, rapidly followed by the 'Charity Works' of Waset is a bit of psychological whiplash, but it works as a good conquest 1-2 combo. Horror at being the Enemy of Egypt, but happy at being aided/part of Egypt.