As the title.

The main thing is if it is possible to 'trade' them via triggering Abysmal Rift Trap, and possibility to build them on planets invulnerable via the trap.

They are extractable via the Mylari build extractor. I know this because I once tried to build 2 on the same planet. I extracted the one, then it wouldn't let me put more than one a planet, so I had to put it back.

I don't know about the Abysmal Rift trap. Based on its description, it sounds like it would not allow the application of any artifacts.

rift traps dont make a planet invincible i think. just immune to attacks.
i think you cant place the gateway on a planet just because a trap got set off.

invincible to all attacks and actions for 12 hours.

usage of artifact is considered as action. But I doubt u can place it either way, because the invic gateway required is probably the one under protection type and a status effect will unlikely be treated as equal.

isn't ppl can use bio vap on abysrifted planet?
I wonder if anyone would care to do the expriment, considering how rare and valuable abysmal is.

well, i'm just quoting the wiki description. what else could "action" mean? abilities only? doesn't make a ton of sense.