A question about Buffs

Let's say that I make a custom version of Vampiric Aura, or any aura. I place some units which of one have both versions or two units have one of each version of the aura.

Will units be affected by both auras? I don't mean the "effect" (as in vampiric aura the effect is life steal etc), what I mean is will both buffs show up on the affected units "Status" field in the UI?

If both auras are using different buffs, yes.

Yes. While different buff spells (such as inner fire, slow...) that are based on the same base spell do not stack, different auras based on the same base aura do.