Don't do that. You didn't. Normally, ghosts. You need to find something of theirs in life, there'll be hair or something if not a body to burn.
These aren't just normal, there shouldn't be able to be ghosts from our worlds here. If nothing else there wasn't enough left of Garrett or Christian at least for there to be ghosts.
Hate to say it, we might need to wait this one out. I'd say learn some kind of life lesson if they weren't constantly trying to kill us.