I am currently doing the same thing with the Epson V750. I have found that the negatives produce much better scans. All of the negatives from the early 1900s and earlier are odd sizes and I use the supplied glass platten to hold them. Most are large enough so only 2 fit at a time and others 4-6 at a time.
They scan directly as positive images directly to the computer in the proper folder and then exposures adjusted in PSE.
I would only scan prints as a last resort.
Once in PSE rotate and crop as needed then use the crop tool to add a white space below the image and write who, what, where and when along with brief comments if detail clarifying the photo.
Then save it.
This is best for me as when shared with anyone of any technical ability can immediately see the who, what, where and when etc. Just by reading beneath the photo.
My family love it and if there is an error of any kind can immediately notify me and I make the change in PSE immediately and resubmit.
Any other questions let me know.

You have so many, you might decide to ignore the expense and send them off to a company that does that. I have done a lot in the past and still have a lot to do, I even have a 35mm filmstrip and slide scanner as well as an Epson 600 and have been telling myself "I'll finish the others soon." for several years now.

The negatives will be more work, scan then convert etc. But the images will be sharper, and you will get the entire image, whereas most print shops cropped negatives to fit standard size paper.

And get some of the disposable light cotton gloves or disposable nitrile surgical gloves (not latex or rubber)* to handle prints and negatives. You want Great Aunt Bess, not your thumbprint. They also have negative and print cleaning kits to get off old fingerprints, dust etc.
Best practice is don't touch anything but your prints, negatives, clean scanner (clean it often) etc. Everytime you touch something else (even your own skin=oils) ditch the gloves and put on a fresh pair.

*Available at some camera/photo stores and on Amazon.

I'd be happy to provide you with an outline of the 'full process', but to do so would take ten times the work it took to actually shoot and process what became the posted image. Suffice it to say, however, that considering the images you've posted, nothing I did would present any problem for you. Pano making is straightforward (and wouldn't be necessity anyhow; I only shot and compiled them because I wanted more real estate/context/potential for cropping if need be/etc. than could be captured with a single exposure). You're obviously practiced in making layers, changing transparency levels, applying different blending modes, and masking as well, so none of that would pose you any difficulty. Similarly, using the Transform>Warp process --in the instance of the image I posted, applied to a) keep the base of the tree's trunk in the same place on each of the layers, and b) to 'stretch' various of the edges and corners in such a way as to provide a sort of 'balance' (since the sort of 'balance' I wanted did not exist in actuality) in what I'd chosen/made toward the overall composition), and that was done 'by eye' as opposed to taking some sort of cookbook-like approach.

None of the above says anything about my motivation(s) though. It also doesn't touch on the parts of the process --that took less time to do than it took for me to write this-- that I now see can/might/should be done differently.