I'm trying to mod the Psion's Soul Mind passive to grant an additional 10% AoE for Echo spells. From what I've read, the steps to do so would be to create a new StatusEffect GameObject for the AoEMult, then stapling it to the Soul Mind ability. When I did that, I managed to get the AoE bonus to appear in the tooltip but it doesn't actually increase my AoE size in combat. The only issue I can think of is the fact that Soul Mind is listed as a FocusTrait instead of a GenericAbility. Am I on the right track?

I don't think that should matter; Soul Mind has one statuseffect linked to it so I don't think there's any reason it shouldn't have two. If it's showing up in the tooltip then the statuseffect should be OK; did you create a new character to test it? If you already have a psion in your party then the changes to the ability might not take

Yes, that's what I did to test it. It's alright, I decided to just add a new AutoGrant passive for the subclass instead, though getting that to work in itself is also another thing I need to figure out...