We are about to go live with a major, non roll back, feature. Is there a way, with SDF, to get a full snap shot of production, so that I COULD roll it back, by just re-releasing all of production with SDF lol

Do they have a sandbox you can go into first? Sandbox is way cheaper than fixing a production environment

We do. We have a dev/test/prod and we're refreshing test again to double check the deployment and changes. I was hoping to have a way to revert the changes JUST in case

Probably not a way to do this with SDF. You can reach out to your account manager and explain this major update that is coming. We've received quotes to have NS perform a full DB backup prior to a scheduled change with the option to restore that backup if we determine that we need to. If I remember correctly, the quote was only for the restore so we only paid if we actually needed to restore the DB (which we never did).