Thanks for the reply. I do have Iris as a secondary healer in addition to Robert (his higher health lets him take more hits from ranged more efficiently than other healers). Is Iris good enough as a secondary healer or should I explicitly use the ones you mentioned?
I do see your point on the tanks; up until this point I've been using my Bandit/Monk/Assassin as tanks when I need them. Taking a closer look at it, for the moment I'll bench Sabine and Lilia for now. I don't think those two will see much use until I really start to move on to events/harder endgame content. By that time my soldiers should be CC and should be able to take over the tank slots, as long as I'm not facing a map where heavy armor is a must. I've gotta remind myself that having a couple of heroes for specific fights are a thing.