Is there any reason to have each outpost tagged with a species?
I guess that depends. Should certain species get bonuses to stuff like planetary detection/stealth/resource supply/fleet supply?
Those don't seem like especially interesting things for species pics, though i am currently using stealth as the only currently possible way to make a species sneaky and spy-like.
For asteroids and gas giants, i think we could go either way depending on how we script it:
1) these outposts provide a resource bonus to planets
in the system, or
2) make them a full-fledged variant of colonies
Or they could just not give any bonuses to resources anywhere. The species bonuses are still relevant to stealth/detection/troops/etc.
Since you cannot build a colony on an Asteroid Belt, removing any resource gathering from Outposts makes Asteroid Mining, and the improved version, completely worthless techs.
Yes, if that were to happen, that tech would simply be removed.
Also, outposts should be fairly 'self sufficient', otherwise all you have to do is break the supply line for one turn and wipe it out completely through starvation without needing to land a single ship on the system, and bypassing any fixed or mobile defenses in that system entirely. We currently have Orbital Farming allowing them to grow enough food to feed themselves, plus a generous surplus, but if they are unable to produce any food, with an 'effective' population of .1, they starve in one round if the supply line is broken.
They will be unable to produce any food either, but they also won't have any population, and will therefore be immune to starvation. The point of blockading an outpost would be to get rid of its resource/fleet supply capability, or to halt production there.