Thanks glad you liked the tutorial to answer your questions

1, there is no huge difference between the two the exposure photographic gives you slightly more control. That said i really only use an exposure node to get the right gamma in the rendered image i prefer personally to do the tweaks in post

2 Yes it's the same keep watching for the correct way to apply AO it's more of a pain to do it correctly than you might think.

Anything else just ask
all the best
Dave