Who the hell knows about Kal or Eduardo but yeah probably good as dead.
Seeing as they chose not to kill anyone in the Hilltop battle save for a few random Whisperer extras, there’s a chance Bertie, Oscar, Marco, and Brianna could appear later on at the other communities. Just wait until 1016 for now.
Gage is still an Alexandrian as far as we know. Hopefully he returns by 1016.