on planet creation, i'm not sure what is the difficulty in it using this engine.
if this engine can generate the planet's features using survey data, then why would it not be able to generate data that's created by the user in creating a planet. both method relies on data/information that is already there, and as you go over the area the engine just generate the features for you?
with planet creation, my simple thought was to simply designed the center of the planet as coordinates (X, Y, Z) of (0,0,0) and create the features of the planet using these three coordinates. these three coordinates are the three dimensions of our human world anyway. and if down the road, the fourth dimension coordinate of Time (T) could be incooperated into the engine then we can have night and day, base on the planet's rotation around its own axis.
from the planet's on it's own axis, then we can create the month base on the moon going around the planet, then the year as the planet goes around the sun, and so on
i do believe that the map above of the observable universe could be created if this engine does not have a limitation to how large it could be, in its scale of creation.