AW Uzume ASAP, the benefits are awesome (5% attack up for whole team just by being in squad, even on maps where you can't actually use her, while deployed an extra -1 cost to anyone deployed after her (-3 total), extra stats for being a lower-cost samurai). Katie is a decent option, though 2% defense is limited on who it helps it's not bad and if you're already using her as a UP generator, y not?

Anelia and Elizabeth are your best options for more damage output, Elizabeth has shorter range but don't let that lower attack fool you, she shoots 3 arrows at a time after CC, and if she happens to target undead while AW, RIP skeletons and liches. Anelia as HUGE attack range as a pirate, with high attack power to go with it (thus better than Elizabeth against armor) and her skill lets her attack FIVE enemies with EVERY shot.

If you don't have a gold+ healer besides Iris, Fedora's a solid investment, you will want at least 2 solid healers and a backup leveled for many maps.