Hi, and thank you for this mod!
A couple of things that would make placing and mining these entities are:
Craft them by an pipe-to-ground, not the same raw ingredients as a regular pipe-to-ground (this can be done in pipe.lua)
recipe.ingredients = {{type = "item", name = "pipe-to-ground", amount = 1}}
recipe.results = {{type = "item", name = "pipe-to-ground", amount = 1}}
Set the placeable_by and mineable to be pipe-to-ground: (this can also be done in pipe.lua)
entity.minable = {mining_time = 0.1, result = "pipe-to-ground"}
entity.placeable_by = {{item = "pipe-to-ground", count = 1}}
These will make it much easier to copy-paste and place these.
About Space Exploration combatibility: I could make a copy of this mod and replace all the names with the space pipes from SE, but I thought it would be a good idea to keep it in one mod if possible.
It takes a few (small) different changes across a few files, and I can provide you a diff if you want.