Turning a nail file into a nail file/knife blade combo - I don’t think this would work very well. For one thing, the nail file is not hardened to the same hardness the knife blades are; the nail file is not hard enough to make a good knife blade. For another, by the time you ground a proper primary bevel on the file, I’m not sure you would have much if any of the file surface left. And if you did manage to save a useable portion of the file surface, it would create a nasty amount of drag when cutting or slicing through something, whereas what is desired in a knife blade is the ability to cut cleanly and easily.
Cut a bottle opener out of the rear of an existing blade - There are combination knife blade/bottle openers out there; two examples are the GEC Beerlow and RRR Bar Back. The key difference, though, is that these blades were designed to incorporate bottle openers from the beginning, as opposed to being a mod later. Modifying an existing SAK blade to add a bottle opener, I would be concerned that the geometry just wouldn’t work, or if it did, that the blade would be significantly weakened.
Scissors as awl/reamer - One can certainly use scissors or a knife blade to put a hole in something, as long as the tip is sharp enough. In my view, however, this is simply another use for the scissors or blade. It doesn’t make the scissors into a combo scissors/awl, for example.
Overall, I think most of Vic’s implements are pretty well thought out, though I’m sure all of us have a few fantasies (bring back 84mm scissors and the technician’s screwdriver) and pet peeves (why doesn’t every hook have the nail file?).