What happened to Bonnie, Mike & Arvo?

I read the wiki since I'm replaying Season 2 atm (still didn't play the final season though) and I remember Bonnie staying at the warehouse and presumably dying but I was surprised to see she actually sticks with the group and eventually seperates with us and tags along with Mike & Arvo. Scrolled down on the wikipage and she doesn't appear or get mentioned in S4. What happened to them?

They should make a mini-series giving us closure on all characters with loose ends.