[Suicide Junkie]

Aside from the fact that population levels have zero effect on ANYTHING spaceborne, you can do that.

Give them something like a P&N Battlemoon, plus some extra hull sizes for those others you mentioned.

The only way to start without planets it to play the first few turns, build that worldship, and then abandon your homeworld. Then save it to be used as a scenario.
Pretty easy to do, so its not that bad.