I tried adding Naufulglebunusilo to a save with this mod, and it does work, but every few tiles, there's the Gleba starting tree thing, but it spawns this mod's version of it, which means when I expand, I get warehouses full of landfill, agricultural towers, green chips, etc.

Interesting. It turns out the way I added starting item containers like the Gleba tree caused them to override the regular corresponding decorative item. This happens without any other mods installed if I tweak the mod to use regular terrain generation. So you could call it a bug with this mod, though it doesn't normally cause any problems since regular terrain generation is effectively "turned off". However, Naufulglebunusilo is a relatively unique case where it uses the vanilla terrain generation items on other planets, so actually causes the bug to manifest.

Luckily, the fix is very simple and the newly-released 1.5.5 has it fixed. Naufulglebunusilo still absolutely has its terrain generation changed by Simple Seablock, and honestly I don't know what the "expected" behavior would be so I don't think it's something I want to tweak too much. But at least it now spawns regular Slipstacks as expected.

All I was asking for was the regular Slipstacks, thanks!