A bit like Rogue, yet not for the whole person, just their supernatural ability. Thus, it wouldn't weaken or effect the person as heavily, when Aurora would channel them. 
I'd say, the extent of the ability depends on how much the "owning" person knows. Whatever their body is aware they can do, she can do. 
I imagine it a bit like "copy cat cells" that replicate those of the person she is touching & is stored in a dorment state until she tries to use them. But only one of these copy cat cell groups can work at a time.