Brent, I'm not at all a Linux Newby--have been using it for years. DA, however, is another story,as I only got on board that train this past August. It's a learning curve--& I've had more than 1 pretty serious bump in the road. Thankfully all but 1 was such that no harm was really done.
I do read documentation & look on Google for answers prior to posting here. I find the documentation to be quite scattered about in a variety of places, not all of which are predictable. I'm sure at some point I'll become as comfortable w/DA as I have been w/CPanel or no control panel at all, but I'm hosting others' websites now, & I'm being as cautious as I would be were I in a mine field. I'm a straight-up coward, & I admit it, so *definitively* re: the box snapshot!
So I'm guessing that a ./build all just reinstalls all configs, keeping anything custom you've put in place provided it's in the custom folder? There just doesn't seem to be a lot of documentation on how all this works under the hood.