So, I'm planning to keep my companions as canon as possible, but I'm not sure about Shadowheart. Most people giving her a ranged weapon, like a crossbow, I recon, because she's not really good in melee. But on the art she's usually have a spear, and doesn't really give an archer vibes to me. Do you think there is a way to make her at least somewhat reliable with a spear? And, in any case, how much does her weapon choice really matter, since she's a cleric?
There is no need to commit Shadowheart to any particular type of weapon unless you are planning on multiclassing her. She is a full caster, and therefore her best move in a fight is going to be
cast a spell, not prod with a pointy stick. This is especially true level 5+ when cantrips get a damage boost that pushes them past weapons.
Shadowheart has a melee and a ranged weapon slot, and you should put something in both, but it can be whatever since you shouldn't be making much use of it. On paper she is marginally better with a dagger, but there are a bunch of good magic spears in the game.
But the important thing is: USE A SHIELD.