Interestingly, regarding point 3, in A New Hope Palpatine doesn’t seem to be interested in relocating to the Death Star, and is instead content to entrust command to Tarkin. (But that’s really because at the time ANH was written, Palpatine was an ambiguous political puppet and an insignificant background detail, rather than a powerful evil sorcerer/mastermind.)
Yeah, he was waiting for DS2 to be built with a shiny throne room, squash court and jacuzzi, before packing up his My Little Pony collection for transport. It was already planned, I reckon.