ok, I reread 37 since I couldn't remember anything at all about it, and wow, rachel screwed up. I'm trying not to be too critical, since everyone sucks their first time, but wow. I mean, I was left scratching my head going "what the heck?". She did make all the mistakes I thought she would, and then a hundred more. She was always impulsive and even reckless, but almost never downright arrogant. And I never thought she'd violate the warrior ethos, and it astounded me that she broke the single most important rule a leader has to follow (even though it's surprisingly common for people to break): The commander's responsible.
As for comedy, they're all hilarious, when they don't try to be. Except for Rachel, but only when she's responding to Marco, so if he goes, I don't think there'd be a good comedian in the team.
for survalience (yes I know it's misspelled, and yes I am so lazy I'm not looking it up), any of them could do it for a mission, ax could do it for the long term searching for pool entrances, and IDing controllers, but without any cultural context I don't think he'd be anywhere near as effective as tobias
For a moral compass, jake maybe, but it's hard to say how much he was influenced by cassie. Tobais might be also able to take that role.
For knowledge of animals, they might be able to google it (yes google existed that long ago) but it woulnd't have been as good as having cassie around
For planning, jake's not too bad, but noone's as good as marco, it'd definitely suffer
For hacking, DIY projects, and knowledge of aliens ax is simply irreplacible
I'm not really sure any of them could be taken out and the team still be able to function effectively without new team member to replace that person