For the Emperor’s palace, you could either use shots of the Jedi Temple if you went with canon Coruscant. Or, if you used Bladerunner footage, the tyrell building could be used for the Emperor’s palace.
I like the idea of using the jedi temple as Palpatines palace, using a few throw away shots of the cityscape from blade runner in a seamless way would be pretty cool, although as a big Blade runner fan I think using the Tyrell building would be kinda distracting.