This is an interesting concept which I had not thought of or heard about before. It caught my interest because I often scan my older 1970s> negs using traditional methods (i.e., Nikon CoolScan for 35mm).
To answer your question about flash damage, I am assuming not, but maybe you can choose one of the less important negs and experiment on it. Flash duration is so fast (but bright), so if the negs have been fixed properly and have lasted this long, probably no harm will be done.
I am presently scanning my own 1975 B&W 126 negs (not for the first time) using a recent model Canon 9000F, but without the film holder (I don't have the one for 126 and laying the negs directly on the glass works quite well, despite taking a moment to align straight by hand). Maybe this under-$200 option or similar will be of use to you and save you some grief in the long run? I can get roughly 1"x1" at 1200ppi, with 2 strips fitting into the lid light area at once. I have attached a sample (shadows/highlights adjusted but no sharpening added).