[Tactician Difficulty]
For Joy Island where we still are, our group was initially and has become:
-Fane (main character): Summoner with 1 Geo. We soon learned that, with enough +1 Summon items (2 rings and a helm), we could get Incarnate Champions (skill level 10 Summon) at character level 6!
-Red Prince: Initially a Shadowblade for stealing and Chicken ability. Became a 1H and shield melee unit due to character concept, but soon heavily diversified. With items, he has Warfare 2, Polymorph 2, Scoundrel 2, Summoning 2, and some other abilities. Summoning Incarnates 'flanking buddies' and disposable mini-fighters has been quite useful, even moreso with Farsight and Power Infusions (and Blood Infusion when summoning on blood).
-Lohse: Initially an Enchanter for magic. Also became a diversified caster and archer to do physical damage more often. With items, she has Aero 3, Hydro 1, Summoning 2, Necro 1, Pyro 1, Hunt 2, and some other abilities. Totems, incarnates, Mosquito Swarm (Necro) and bow abilities have turned her from niche use into continuous relevance.
-Beast: Initially a Shadowblade for stealing and Chicken ability. Became the group's primary archer because long range killing was more useful than stab-o-port (Backlash from Scoundrel) and melee often got crowded with Red Prince, totems, incarnates, and enemies in close proximity to each other. With items, he has, amongst other abilities, Hunt 2, Scoundrel 2, Polymorph 2, and Summoning 1. Summoning was so useful that he also learned this.
[Overall]
We struggled early game because of split physical/magical armor damage and general newness to the game. Reading forum posts and guides helped a bit, but after realizing that more units on our side meant battles were easier and that focusing everything on physical damage made everyone more 'compatible,' combat became less frustrating overall. We also learned, according to one forum post, that magic damage becomes more useful later, perhaps starting in act 2 or 3. At least for now, we intend to focus on physical damage and the occasional Atrophy, Knocked Down, and Chicken status effect on enemies.