A few things:
- 1. The pipes don't place as owned by the player and so show up red on the minimap
- 2. When placing and harvesting the 2 sided connection pipes it gives a one sided connection pipe back - not so much a bug but just annoying having to keep re-crafting 2 sided pipes
- 3. Because all the different types of connections are different pipe entities they don't work with blueprints (always reports missing items)
For 1: That can be fixed by setting the force when using createentity in your control.lua script (unless it was intended)
For 2: You should be able to duplicate your existing pipe entities and have a second set that harvests to the double sided pipes
For 3: Blueprints only work if you've done #1 - blueprints don't let you create them out of non-player placed items apparently. But, you could also make a new crafting category tab with all the different styles of connecting pipe available to craft from the one-sided connection pipe item. That way you could have them available in your logistics network using auto-crafting and could blueprint copy-paste an existing pipe setup.
Having them in a different recipe category would keep them from cluttering up the existing recipe category that a normal player would use. You could also put the item description as "Pipe custom connections: N/S/E/W" while keeping the entity name the same (making them distinguishable from each other) so when it's placed in the world via your control.lua script or a robot it still reads "Clean pipe" for the name (entities in-world have no item description attached).
If you want to get ahold of me I'm almost always on IRC and Discord.