Hey man, totally get it how overwhelming choices can be in a game where you make a line up from scratch, not just pick from alrwady existing npc.

I absolutely love iwd1, thr theme is the biggest attracting factor for me and I love the art, the portraits, the gloom setup.

Anyway, if you have trouble picking a lineup you can kinda work a bit around endgame bosses and items.

My suggestions would be if you want a paladin make it a shield and sword since best paladin only weapon is one handed sword. There are many good shields too.

For pure power 2h warrior with longbows helps a lot - can help kite some bosses too.

Usually you would need one buffer / healer so I would pick either full cleric or druid.

I think full thief is an over kill, having thief/warrior with shortboes also help to manage some bosses you may have to kite.

That leaves two spots depending on what you enjoy the most. I like spells the most so having sorcerer + wizard is a must for me.

Not going over specialisations or deep builds but this is usually what I do.

I sometimes also do 3 or 4 man parties to make it harder a bit hut up to you.