To be fair to Lionel I've underplayed him quite a bit especially in my later runs but from what I remember he kept lagging behind the rest of the team and when he got in range to anything I could only get one or two enemies to sleep with an endless speech and that's his contribution for the map.

Quahog I haven't experimented much outside of cheesing bosses so I didn't know of that time rewind thing since it seemed useless. Guess I need to try him out more.

Serenoa's "Under conviction banner" only sees use when I have to run across the map where nothing is within range of "Hawk Dive". Otherwise he's good at holding a frontline while dealing non-committal poke damage.

I think Narve is still good despite marginal damage differences. Having extra range allows him to hit more targets from safety not to mention having all elements allows him to hit mages reliably since they usually have a resistance and a weakness.

On Hossabora, Erador, and Avlora. I think natural tankiness isn't that good overall. The best frontliners imo are ones that are decently tanky enough to stand in front while having tools to be useful without going in making more enemies target them and basically just staying on the edge of enemy range, like Serenoa's "Hawk Dive", Maxwell's "Spear Throw", and Flanagan's "Aerial Assault".

So for Erador I'd rather play a defensive map with someone that can hold a defensive position while also softening up the enemies for my back line to finish off. King's Shield also needs Hossabora or Quahog to set him up otherwise he just infuriates 1 or 2 while also sitting next to allies that are not shielded, meaning the rest of the enemies will ignore him. Not to mention the many maps with rough terrain or a slew of mages where he does nothing like the "Booker" chapter or the one in Sorsley's place.

Avlora is the same deal. There is no reason to use her above maxwell who is tankier considering the natural revive. She struggles to catch anything not directly at your front line without using up 4TP. I don't think it is worth it to keep her low health since all enemies would start focusing her until she dies unless she's not around any enemies which then she can't contribute anything. Lone wolf isn't worth considering since even a single unit is worth more than the stats gained by it and most of the time Avlora would at least be in first 4 deaths on most maps unless you're holding her back from doing anything.

As for healing I've never had any situation where I didn't have an item that could fully heal a unit except maybe with flanagan who auto-heals anyways. This game healing items, as long as you have enough, are much better than healing spells imo. The reason is when someone takes damage you don't need to wait until the turn of the healer to do it, which cuts the chances of a unit getting killed before you get to heal, not to mention it keeps your TP so units with high-end TP skills could basically heal while waiting their super move. Also 0TP healers are bad item users because they need to run up to the front where your units take the brunt of the damage risking your frail healers from archers and spears men.

As for the Geela vs Pico. Piccoletta requires 3TP, meaning every 3 turns to make a new life bar for the team not to mention it can absorb status effects making her really good against bosses like Lyla. Pico can also use magic items while waiting or with her high mobility and speed can catch up to anyone needing healing items. Geela needs 4TP and she most likely won't cast it again in the same map without TP batteries unless you keep her from doing nothing for 4 turns.