So i was wondering this about the interaction between the two game systems this would have to change overall the PI system for it to work when generating the arena so i had an idea in mind that could potentially work.
The colony planner simulator this would open up a UI similar to the ship fitting simulator but rather it would be a map to place all your buildings on as well as future proofing for newer buildings later on in eve vanguards development.
Now that does mean all the factory/storage would be removed from the PI planet map as they would be inherently within the colony command centre its self except for extractors they will still remain outside the command centre. As for buildings such as spaceport they will be integrated with the command centre that once you get to lv 4 upgrade you will unlock the feature to use a low to high orbit transport and then the lv 5 upgrade would be a bigger one that can hold far more.
It would also have to change how the power grid/CPU works for the colony due to the removal of the planet links from building to building where all buildings now recede inside your colony.
Yet it does not mean the end for links they will still be in the colony just more scaled down.
As for another new feature for the colony modules that can influence the arena for vanguard players these also consume power grid/CPU but could add say mountable turrets to the battlefield or resupplies cache for those defending your colony.
This would also allow for saving a possible blueprint of the colony so you can simply create a new colony a paste the saved blueprint thus acting as a quality of life instead of the choir of redoing it all over from scratch for each colony.