I have played the final 2 fight sections (Camp Bronze Lake and The Plague) several times over the last 3 days and I have found that the following is a constant when using only the PS4 Controller (on the PS4):

1. I cannot select any of the marauders who I am fighting with.
2. I cannot put "Eye for an Eye" on anyone but my fairy.
3. I cannot select the plague worms which spawn in the last fight.

When I add using a mouse, I can select the plague worms.

this seems to me to be a bug in the game. If it isn't let me know.