I doubt Coco gives two shits about Cover considering the things they've been actively doing to make her leave on her own to save face (anyone who honestly believes it was just a mistake that gave a bunch of bugmen moderator positions in Coco's chat is a fucking idiot). Coco's concern is probably for the other girls.
As for committing suicide, I find that unlikely, but I do foresee Cover fucking up again with the other JP girls and pissing off enough of them that they start bleeding talent until they're left with just Azki and maybe one or two others. Coco leaving is probably the beginning of the decline of Hololive.
I'm not so sure about that. What's Aqua going to do for a living if she leaves Hololive? Her social anxiety is bad enough that she'll never be able to hold down a normal job. Unless some other vtuber group picks her up or her mom hooks her up with a job thanks to friends or family, Aqua's pretty fucked if she leaves Hololive, and she probably knows that better than anyone.