Thanks!
What is the final sanding grit. 320?
AFA the wood, generally something around 320 min, but occasionally 400 papers, or 320/500 Norton softtouch contour sponges if obvious scratches can be seen. There's a good chance that in hard, fine grained wood, you will still see 320 grit scratches if there is any stain/dye/of color/toner in the initial finish coats. After saturation with thin shellac, the grain raises a tiny bit. I sand all over with the Norton softtouch sponges, grits from 400/600 through 800/1000 as "necessary".
After that, generally 1200 or 1500 mesh between coats, though in rougher areas the 800/1000 sponges are ok, too.
I use Naptha ("white gas") for lube where necessary after finish coats are started. It won't cut shellac, and it evaporates fast. OTOH, is is highly flammable. Mineral spirits stays wet longer, but it will bleed into the wood and take longer to dry, if the wood is not completely sealed.
However, if i have to use significant abrasives after the saturation coat, i recognize that there is something else wrong with my application process. Too much too fast, usually. The old guys got the "under glass" finish with virtually no abrasives after the pumice filler coats on the bare wood. (I don't use the classic pumice method, except on some antiques. Full grain fill is generally not my preference on grainy wood, and fine pored woods like we are discussing don't need it)
What will you use for a final finish?
It's done.
Or, depending on your view point, it never is.

It will slightly darken and the mahogany colors start to blend more on it's own after some exposure to light.
I am using Tried & True oil over the shellac, but it only takes a few drops to do quite a large area. There should be none visible after an application and it should not exactly be "wet" even as it is applied. If there are scratches or anything like that from storage or assembly, i'll touch them up with some scuff sanding and a quick shellac polish.
Long term, I might wax it with Trewax (brand)
Wax helps avoid some scratching due to blows sliding on it.
Light buffed out wax does not interfere with shellac (for touch up) but i'm not of the opinion that it helps. So there is that consideration. OTOH, I clean off repair areas with naptha before commencing & continue to use if for the abrasive lube.
Oil in the wood (before shellac) will darken fast, and darken more over time.
Faintly, rarely, oil over top, adds some heat, moisture, alcohol protection with little darkening beyond the wood and all the finishes slightly changing with time.
I kind of prefer a "dull" "rubbed" effect finish. Sometimes rubbed out with 0000 steel wool, or 3M synthetic gray (non-abrasive) pads is were i end up for personal stuff. Oil over the shellac, &/or wax, buffed out with a soft cloth.
You did ask about historic finishes.
The modern response is to attempt to provide a bullet proof, never-care finish that will last "forever" (Usually about 20 years, but maybe 50 if no significant damage occurs) The production approach would be to clean, sand, tint/dye/tone wood & or finish; spray 2 - 3 coats of armor like finish. A cheap system might include consumer grade poly (which has actually very little polyurethane in it but is way tougher than shellac). A "higher end" finish might be conversion varnish. What might be considered the "ultimate" these days would be epoxy sealer and polyester or polyurethane high solids piano finish. The modern system attempts to provide a finish armor that will never crack, fade, or scratch. OTOH, when it does, it requires stripping or very intensive repair efforts, some of which are best not taken in a residential space.
The old methods accept that scratches, damage, "battle" scars are inevitable, and provide an easy means to repair, blend, or mitigate over a lifetime of light attention/maintenance. They are easy to strip and re-apply, and AFA shellac are mostly innocuous to humans, though some of the solvents like naptha and mineral spirits are not benign, and all including ethanol are quite flammable.
From about the 1600's through about 1929 these were pretty much the only finish methods available. Some of the old stuff still has original finish on it, and some still looks like it is shining under a coat of glass. With every other patina imaginable based on tastes/preferences.
No finish system (except possible consumer grade "Poly") is a slam-dunk. They all require education and practice/experience.
It is best to run some test boards/cards before choosing a finish system. Then run a full test board the whole way through right along with every step taken in the actual finish. Label it step by step, and keep it as part of the archive. this would include the solvents, retarders, any toners, etc, etc by percent for the finish batches as they are applied. I don't quite do that with familiar processes, but have them laying about or stored in the loft for systems when they were new to me.
BTW, i truly hate finishing and avoid it afa possible.
But it has been necessary as a woodworker to be somewhat conversant.
Nice when the project permits hiring that part out.
Good luck with your choices!
smt