I think that what happens in practice is going to depend completely on the kinder concerned. Can you meet with the head teacher and see what they intend to do? From what you say it seems as though your DD would need to be pretty much 1:1 supervised outside, and would be OK to share the aide inside.
Also, some kinders refuse completely to change pooey nappies. I'm not sure whether having an aide would make the situation any different, or whether you would still be on pooh-call, but this is something you should check out too.