[@Lucidnonsense] I don't have numbers for how dense the empire is as a whole, but it would likely vary from planet to planet. One planet might be a super dense ecumenopolis- with all the cyberpunk sprawl and dystopia that entails, another world might be agrarian or like a resort world and have considerably less population density.

Not sure about cloning, it's definitely possible and an interesting idea to take-the empire is a large nation and several planets and systems act more or less autonomously within it, so it wouldn't be a stretch to say maybe one of those entities utilizes cloning technology. But in general I'd say the empire probably has enough natural population to expand without needing clones. They use robots a decent amount, they probably use them to cut down on the need for as much manual labor.