Violet

Simms could be alive in the vents if she isn't spaced, too in shock to explain anything immediately so her logs are still relevant and perhaps she has more to say when everyones in bridge Ops

For Carter I think they should still both have an optional death and I'm thinking that contrary to what would be expected he should only live if he doesn't make it to his room, that way you get a dead Carter and an ominous message or an injured Carter who ended up falling down somewhere in the lower levels and was presumed dead by the organism and Eisele finds him in the same general area

If both are alive Carter will defend Simms believing she had an adverse mental reaction to almost being spaced

Depending on paths he may either emphasize compounded emotional distress and sympathy that it was only a momentary lapse in judgement(caretaker), or suggest the need for medical intervention(the fixer), possibly resulting in her sedation for a similar time frame as Williams

If just Carter is alive his path will determine his thoughts on the matter with caretaker Carter hopeful that she got back on the ship somehow and again going into the notion of Simms being in distress because of her near death experience and will believe that mimic Simms dying or being shot is actually her and will feel guilty for her fate, especially if brianna loses an eye but won't hold resentment against Cooper or Young in a self defence scenario

while the fixer is adamant that it's not Simms although the other characters may believe he's also suffering some delusion to deal with the idea that Simms attacked him

If just Simms is alive then Carter's message is the only word on the situation. Simms will necessarily be briefly left alone when mimic Simms attacks Young, creating confusion on if she is the same person or not regardless of Carter's survival and the cameras would glitch so it's unclear that Simms didn't randomly attack anyone when coming across her again in the same state after possibly being shot and/or falling

It would then be a choice to sedate her which may be affected by the traits of who's in charge and there's a non zero chance that Simms would be expected to make a case for not murdering Carter but would obviously be exonerated by the mimic reveal

A surviving Simms would offer a second chance at the path where Williams reveals everything if Anders had been unable to look into her suspicions(the more Simms logs found the better here)

A surviving Carter would necessitate Cooper being woken before the crash and gearing up would have a bunch more bickering for answers and presumably less ambiguity around the fact that they crashed but that's not a big loss.

Carter and Simms survival would be factored into the flashforwards 'no more games' and 'waste management' so that all three flashforwards would involve the fate of a player character and an NPC but both would be difficult to move, Carter because he's got at least an injured leg and Simms would be dependant on wether or not she's woken up from recent sedation or not.

Both will remain in bridge Ops until everyone heads to the SEV and if they're both alive Mitchell can be convinced to stay with them to ensure there safety