Is there any way we can assign specific layers to be visible in separate plot layout pages and not have the layers visibility be global across the entire program?
Yes, this is possible. You can use a specific Scene for a specific layout to adjust you visibility settings per layout and keep the layer visibility in Plot view independent from those settings.
But will the scene selected to be shown only on the "Iso" view layout always appear on that layout page? If I create a scene called "ISO" and then apply the layers I want in that scene and go to the ISO layout it will assign that scene to that layout view only? If I then switch to a "Plan" view it can automatically change the scene to a scene called "PLAN"? OR whatever I want to name the scene for that specific layout?