Epson does have a updated driver for the V500. Your software will do the reversal of the negative to positive. You can also try ViewScan and SilverFast and compare results.

Even better is the select subject tool. This will allow you to easily select the subject, use the select and mask tools to refine the selection, and move the selected to a separate layer without the background. It is in PSE 2020 and newer, and has been available in Photoshop for a while. It has taken the time it took me to select and mask for compositing from several minutes down to seconds.

The Canon EF-S 10-18mm f/4.5-5.6 IS STM is a lighter and less expensive alternative to the Tamron 10-24mm F/3.5-4.5 Di VC, for your APSC Canon body. Both have great image quality. On the used market the Canon lens holds a greater amount of it's original value. The STM motor on the Canon makes it more useful for video and vlogging. The Tamron is 2/3 stop faster than the Canon, which at 10mm is probably not that big of deal. One important note on Tamron lenses is the focus and zoom rings turn in the opposite direction (Clockwise) that Canon uses. The choice is yours and I think that you can't go wrong with either.

Lamination materials are not archival. In other words the laminating plastic contains acids, that will eventually discolor and destroy the print it is supposed to protect. If you are laminating a print made from a digital image, it's probably ok, as it can be easily recreated at a later date. I would advise against laminating any print that was made on conventional photo paper, using enlargement techniques, as it is impossible to reproduce an exact copy. Display of those prints needs to be in properly matted frames and using museum glass, and subdued lighting.

For high quality I would agree that the Epson V600 or V850 Photo scanners, coupled with ViewScan or Silverfast software are great. The downside is that they are painfully slow. Camera scanning is certainly an option, to give you a very good level of quality, and allow you to capture as raw files rather than tiff or jpeg. A 24megapixil camera with a macro lens capable of 1 to 1, should allow you to (scan) 35mm slides a little over 4000 dpi. To reverse negatives I recommend a plug-in for Lightroom Classic called Negative Lab Pro. I'm attaching a link to a video where the he is able to scan up-to 600 slides/negatives per hour. https://www.youtube.com/watch?v=42RXRqZDhe0

If someone else did initial edits in LrC, and he copied the files onto a flash drive, they will not include the edits from LrC. If the files were exported from LrC, then the edits will be in the new tiff files created by LrC. If this is the case I would bypass LrC and just use Bridge to manage the files and open the originals in PS. Lightroom, in all flavors is a totally non-destructive editor, and never re-writes the original files.

If you are coming from LrC into PS, LrC will create a second tiff file with a new name of filename_PS to indicate it was edited in Photoshop. So you will end up with two tiff files, the original scan and the edited one. It is strongly suggested you keep the original scan file and do not overwrite it with the edits. The reason I suggested PSD rather than tiff for the output is I don't flatten layers when I complete edits, incase I want to re-edit from the point I left off. Although, tiff will retain layer information, the resulting files are much larger than their PSD counterparts. Your friend looking over your shoulder, may learn some Photoshop along the way, and may want to play with them at a later date.
When you complete the project, use your operating system to copy the files over to his flash drive.

What you are calling a Heli Coil is used on some cameras to reduce a 3/8" x 16 thread down to a 1/4" x 20. The adapters are common as motion picture and large camcorders use the larger thread for tripod mounting. Some tripods also use the larger thread to attach the head to the legs. 35mm film cameras, DSLR's and mirrorless cameras tend to use the 1/4" size only.

Rather than use the Export Module in LrC why not use the Print Module? Not only will the Print Module allow you to set-up presets for various printing, it will allow you to create an appropriate Jpeg for the final print. If you are using a calibrated workflow it will also allow you to imbed the ICC protocol for the printer at the lab you are using.

I'm assuming that you are using Lightroom Classic LrC for this. Set-up a temporary directory on your internal drive for this. Create your catalog and import the files from the flash drive to a folder on your internal drive. Tiff files are exceptionally large, and take an exceptionally long time to load and save on any external (USB) device. The flash drive is designed just for temporary storage. Figure the PSD files will be about the same as the TIFF's or more if you leave them un-flattened. Add another 10% for the overhead of the LrC catalog and previews. Just make sure that LrC is set to build standard previews, not 1 to 1 or Smart previews, since it look-like you are planning to do your work in PS. Note you can place the catalog and pictures in the same directory for this. When you are complete copy the folders over to the flash drive. Wait until your friend has uploaded the catalog and photos to his computer and checked them out before deleting them off your internal drive.

Your entry level Canon does not have focus confirmation with non EOS compatible lenses. You would be better off using a Canon EF-S 60mm Macro or Canon EF 100 Macro and a device like: http://www.skier.com.tw/web/shop/shop_in.jsp?pd_id=PD1599466967388. Alternatively, you could get a tether cable, tether into Capture one, and use the live view focus peaking feature to set focus.

I work at a Woodcraft store, where I sell machines and (until Covid) teach woodworking skills. I have used all flavors of Sawstop saws in demos, teaching and working around the store. I recommend Sawstop saws at what ever level. The builder’s saw the OP referenced, not only has the safety mechanism, but it has a superior fence system and better dust collection systems compared with other builders’ saws. The downside is it is double the price of most other premium builders; saws like Bosch, DeWalt, Skilsaw and Metabo. With that in mind, it is still the superior saw.
Where Sawstop becomes more price competitive is in cast iron saws. In fact, Sawstop is the largest selling manufacturer of cast iron saws in the United States. Sawstop’s 3hp 220V Professional Cabinet Saw Is less expensive than comparable models from Delta and Powermatic.
One advantage that Sawstop saws have is they come standard with a zero clearance insert, and they are the only saw I know of on the market that allows you to set the blade to a bevel with a zero-clearance insert in place. They are also the only saw that I have ever set-up that does not need calibration as it ships from the factory. It is true that when the saw fires you must replace the brake cartridge $80, and likely the blade. And yes, I have tripped the mechanism both for demo purposes and inadvertently. Be wary of metal around the blade. If dealing with wet wood, you can disable the brake feature. The saws will take up to a ¾” x 8” dado, but you need a dado brake $100 and a dado insert $30 on a jobsite saw.
Like all power tool manufacturers, increased demand and decreased supply due to covid has resulted in many backorders. Currently Sawstop is running 7 weeks behind on shipments. With the way freight is going plan on 8-9 weeks until you receive your saw, unless you happen to find a dealer with one in stock.

I know these are some basic things, but they can cause the behavior you are describing. 1. Did you create a layer mask, as part of your smart object which is hiding the effect, after you applied it? 2. Did you change the layer blend mode to something other than normal? 3. Did you change the order of the layers? In other-words is there a layer over your smart layer which is hiding the effect you are trying to create? If you rule out these basics I would suggest a chat or call with Adobe Support.

Color negatives are considerably less sharp than color sides and black and white negatives. So I was taught (in the days before Photoshop) when shooting for compositing always shoot color slides. I interpreted the OP's actions as trying to composite a color correction layer, over the negative, which will reduce sharpness. If you use the color correction as a gel, between the light source and the negative it should work with no loss in sharpness. Just remember to use diffusion with a printed gel.

What you are proposing may work but will result in a loss of sharpness, contrast or both. There are easier ways to accomplish your objective, without spending tons of time or effort.
If you use Lightroom, “Negative Lab Pro” is a plugin for Lightroom 6 & Lightroom Classic, that can successfully invert photographed negatives. It is available here: https://www.negativelabpro.com/.
Vivid-Pix Restore, which is designed to correct color shifts in scanned photos will work after conversion to tiff or jpeg. Its available here: https://vivid-pix.com/.
Capture One has a utility for inverting negatives, however it is only available in their “Cultural Heritage Edition”. This tutorial can work you through the process in Capture One without having the utility: https://medium.com/@benjamin.bezine/scanning-film-negatives-with-capture-one-e707d52c9b7a