I don't think either Jonathan or Andrew deserves to die. In fact, keep them around for a long long time - they were funny.
Andrew was just a hapless groupie to Warren. He didn't do anything bad because that's what he wanted, he did it because he knew it would please Warren if he did. Like so many people in this great wide world of ours, he was a sheep. Baah.
Jonathan knew that alot of things he was doing were wrong, but he was threatened and intimidated by big bad Warren. He even was on to the scheme that he was being used and would end up being killed or left for dead or turned over to the police and blamed for the things Warren did. Unlike Andrew's sheep, Jonathan was the scape-goat. Neeh.
So, you see the critters shouldn't be killed.
Whether Andrew comes back or not is a moot point, but PLEASE bring Jonathan back - he's been on the series from the very beginning and needs to stay until the very very end.