That's a glitch, the other red with no name isnt a player. I've had it happen before, it's really weird
Yes, we actually voted the unnamed player out and it continued the game like normal. So if you have one of these guys on your server, don't vote them out, it's a waste of time.
If they're imposter it really sucks though. Pretty much once the kill cooldown is over it kills anyone that gets into the kill range of it and you cant kick it out.