This is done via Save Editor... no Mods are installed...
I replaced the Squadron Pilots Scene with these Scenes.
Pet Rock: "MODELS/PLANETS/BIOMES/COMMON/INTERACTIVE/PET_ROCK.SCENE.MBIN"
Derelict Endroom Terminal: "MODELS/PLANETS/BIOMES/COMMON/BUILDINGS/PARTS/BUILDABLEPARTS/SPACEBASE/ENDROOMS/TERMINAL_CORE.SCENE.MBIN"
PreBeyond Anomaly Weaponcrate: "MODELS/SPACE/ANOMALY/PARTS/WEAPONCRATE/WEAPONCRATE.SCENE.MBIN"
Atlas's Warp Cell Stone: "MODELS/SPACE/ATLASSTATION/MODULARPARTS/INTERIOR/INTERACTIONSTONE/INTERACTIONSTONE_1.SCENE.MBIN"
I use Expansion Rooms to load these as it has a Central location...
Before doing anything in the save editor... Be safe and make a Backup before changing anything...
You can replace the Scenes with many other Scenes to load in and check out... Most things that have a function will still work as they should, but not all.
E3 Diplos and Rhino can be loaded in but only in the Manage Squadron Menu... all rooms that load a Squadron Pilot must be deleted before trying them... this will go for anything else that locks up the game when entering the Base. Some things will spawn multiple items if the object is movable like a red ball...
Nothing shows for other players in Multiplayer....but Items looted can be passed to other players.
If you do crash you will need to revert your Pilots back to normal NPCs
for example
"MODELS/COMMON/PLAYER/PLAYERCHARACTER/NPCGEK.SCENE.MBIN"
"MODELS/COMMON/PLAYER/PLAYERCHARACTER/NPCKORVAX.SCENE.MBIN"
"MODELS/COMMON/PLAYER/PLAYERCHARACTER/NPCVYKEEN.SCENE.MBIN"