I know sub males being able to breed is a rejected suggestion... but what if they could breed with lionesses that were up for reverse breeding?
Like have a dropdown of which male to select when sending a heat request? That way they arent breeding within the pride but have the option to breed outside of it, and you still get the cubs... and of course make sub males more useful outside of just keeping an heir around.

Just an idea... thoughts? Criticisms? Concerns?
What do you folks think?

Maybe the submales could have a breeding cooldown too?