I’m assuming that they work similar to ‘pets’ and their stats are actively calculated (like a pet build can switch out a piece of gear and the minions become immediately affected).
So if I use buffs or get a temporary proc which boosts something sharable with the Guardian(s), they’ll be affected as well?
EDIT: Doing some crude testing it appears as if even completely solo buffs with no AoE (such as the Untouchable shield’s 4% OA) applies. But it’s a bit hard to tell for sure, need to test with something more obvious. Buffs with an AoE component clearly work but the question is if its because my own stats are amplified or because they fall under the AoE.
As far as I know, Guardians do not benefit from flat damage (as they deal no weapon damage) or your attack/cast speed (they have their own that can be increased through select skill modifiers).
Any buff that applies to you otherwise applies to them as they scale off of your other stats like OA or % damage, their damage can be converted as well. They are not targetable and invincible so stats like DA don’t matter.
Worth noting as well in this regard that you might see graphical effects from skills like Blood of Dreeg around them - this doesn’t mean they double gain from it. It’s just the nature of auras projecting on nearby allies and does not do anything stat-wise beyond the aura buffing your character and by extension buffing them.