Same here, I'm around level 8 with the same group you have as well, but when I first encounter Hiravias and attempt to recruit him. I ended up with 5 member (Hiravias doesn't even show up as his portrait in the team member portrait area, so I can't initiate any dialog or action).
When I travel back to stronghold, and attempt to change around the characters there, still nothing worked.
Any fix for this yet?