Try it!As of now, the download section shows the latest nVidia drivers for Sierra marked as 378.05.05.25f11. Haven't tried those.
I have not installed the last 2 or 3 Security Updates on my 10.12.6 Hack. Can I just do the new 2019-002 update and not do the older ones? Or do I need to go back and do all the ones I missed in order?
Yes, you can. The Security Updates appear to be cumulative so you can just install the latest one to get all current security updates.
There's no reason to use Clover 5000 versions with Sierra/High Sierra, they're only intended for use with Mojave 10.14.6. Stay with what already works for HS obviously.DON"T try to upgrade your clover to 5000 or higher