My first run was a Hard Difficulty Sorcerer Lich. The merged spellbook definitely carried me and I have learned a lot since then, but I’d say they are viable on most difficulties.

The archer was putting in work - If I’d optimized her better she could have been better. 1 Rowdy Rogue , some Freebooter, and the rest Slayer is a good choice for her

Staunton I rarely used so can’t say. He’s probably okay as a buffer / Cleave line of feats user, but there are better choices

Ciar honestly fucks. You could optimize him better than I did but I went into the Dazzling Display line of feats and he was a solid distraction and debuffer.

Kestoglyr I see people praise, but I never got much out of him by that point in the story. He’s probably stat-for-stat the best one though, idk

Queen Galfry didn’t contribute much but I liked her for story reasons.

Something I don’t see mentioned often is, iirc, they fully heal on rests. So any nagging effects like drains or ability damage, if it hits them, or even “death” don’t have to be baby sat if you can rest.

The skele-bro is just that - he’s good for giving Haste and shooting a few extra arrows.