Alright, in short, the Empire is just fascist. Although it's different in a lot of ways than in real life, because magic exists. Their overarching ideology is almost a copy and paste of what Nazis said about themselves, except with Jedi instead of communists. The Empire blames every problem it has on non-human species or Jedi provocateurs. Their ideology is built around managing a huge central state and expansionist military operations. All organized religion is illegal too, but that's a sweeping measure to stamp out any potential Jedi. You gotta remember this is a fictional universe where one religion has absolute proof it's correct and being a follower gives you superpowers.

I think I remember one book slyly talking about the empire's need for child rearing, so I'm pretty sure they were heteronormative.

All the aspects of Imperial ideology are about channeling power up to the Emperor, but power I mean actual magical powers. The more people who live in fear, the more the Emperor gains mastery over the dark side.