One thing that really concerns me is putting all these planets in a single play field. Did something similar like this back on the Sins of a Solar Empire server when it was still up. There was frequent lag and play field crashes. Have you tested all of the planets in a single play field yet?
I don’t know that server but technically / performance it is better to have multiple planets in one orbit rather than multiple planets in multiple orbits.
But of course we never had the usecase of over 15 planets in one orbit. We have to see how it goes but if I encounter warp problems along the testing state I split it to two orbits again.