So like you, I started playing on Normal. I made something like a straight Vivisectionist in Kingmaker, and my builds for most of the companions were complete and total dogshit. I moved it up to daring with Wrath, and I made a really bizarre gish that was inefficient but fun (Fighter-Wizard-Bard-EK, the one point in Bard literally because it removes the arcane spell failure rate on all shields with all spells, not just bard spells). Then I upped it to Core, made an Aldori Defender - Duelist evasion-tank stacked up with every riposte-related feat in the game. Hard and Unfair require you to insert a bit of cheese into your builds, but Core really brings a lot more features of the system to life than does Daring, and it offers up a great incentive to figure out the little things.
For example, Woljif starts as an Eldritch Scoundrel. A lot of people try to move him into Arcane Trickster, but this is a really bad move - his spell progression will remain just as slow as it was before, and he'll get his BaB bonus downgraded from 3/4 to 1/2 for those ten levels. The AT capstone, which lets you apply sneak not just to rays and ranged-touch spells but instead to AoE spells as well, is pretty bad on him because he caps out at 6th-level spells and his saves for things like fireball aren't that great. So he's actually better to take to Scoundrel 20, with his spellcasting mostly being used to pack party buffs (and transformation, which gives him a full 20 BaB). ...but then you also might notice that level 3 in rogue is the fastest that you can turn daggers into DEX->Damage with Finesse Training. You can straight up stop taking levels in rogue and swap him over to a full-BaB class (Slayer, Ranger, Fighter, Bloodrager, etc) and he winds up shitting out damage at the cost of less utility.
Seelah is built to be your early tank with those feats in dodge and shield focus. Eventually, you'll come to be mildly annoyed at the fact that she has these feats, because paladin is a lot better with a two-handed weapon. She still brings insane utility as Paladin is one of the best classes in the entire game, but she falls off of being a reliable tank pretty early on, unless you dump a feat into Armor Focus: Heavy and grab the Mythic feat for Heavy - Avoidance around level 7/8. And so in my most recent run, I turned her into a shield bashing Slayer with a two-level dip into PLD for CHA -> Saves, and Shield Focus ceases to be a wasted feat. She spits out damage at the cost of utility.
Sosiel also has one of the worst fucking builds imaginable, and once you understand the system better, you come to hate that fucking character. Cleric is such a good class that it doesn't ultimately matter - he's still really useful - but shit like Extra Channeling, Toughness, and throwing a feat away on Heavy Armor proficiency is really fucking wild.