Hi Jon,
As to 1. Holdout in the Outliner is per Object (/Collection), a Holdout Node is per Material.
As for question 2. I don’t know, I’d try the 3 different Options and see which does what I want (the Tooltips might also be of some help).
And 3. I don’t know what you mean by Occlusion Culling.
I expect that someone else will be able to better help you here.
