Well I think I figured out the IVS/snapshot issue and having it save snapshots to my NAS. If you want IVS to work you have to go to Event -> Smart Plan -> IVS button (light bulb). Once you have it clicked it should turn orange. Then click "Save". From there you can then configure your IVS rules, period it runs, storage location, snapshot period, etc...
I've been staring at this menu GUI for days trying to figure this out and I finally said "Lets see what Smart Plan is". Sure enough, you enable IVS from there. Hopefully this helps someone in the future trying to setup IVS. Whats crazy is I have another Dahua camera running with IVS/snapshots and at some point in the past when setting up that camera I went into this same menu on that camera and enabled the IVS "Light bulb". Not sure why my brain didn't remember that. I have no recollection of that at all...
Any way, I love Dahua cams but, damn, they need better documentation. This is an excellent camera. Thinking of picking another up.