The playfield does not look all that bad. The shooter lane's particularly decent. If you did not have the HSA clear coated one, a good cleanup and polish could probably have done the trick.

Are you redoing the cabinet?

Personally, I take tons of pictures and use the manual when needed. I have never had a problem. The harnesses are really hard to mix up because of the keying and the colors. I found cleaning them up to be a real pain. Also, they retain a certain amount of their original shape. This is partly a good thing because it helps figure out where switches and lamp sockets go, but because I'm never able to put it back in the exact same original place, it requires a bit of refitting.

On the LOTR I just did, I notice the exact same thing. The inserts sockets are the same and the coloring is very close. So I ended up mixing up a couple. But that's a trivial fix. I found 2000's Sterns easier to work on than 1990's Ballys.

Are you doing a full cabinet restoration with decals?

I recommend switching to stainless flaps or at least protecting the blue steel flaps with some wax.
After a very wet winter in California the Venom flap was all pitted with rust.

They likely come with the original blue steel. Wax might do the trick though it'd be nice to have other more durable options. I got my flap chrome plated but it's too thick and affects the game play - air balls, deflections, missed shots. The Venom ramps is hard enough to hit as it is so I ordered a stainless flap.

A rotisserie wouldn't hurt.

Absolutely but you pay shipping or I ship it free in exchange for your old playfield.

You might be able to find someone local who can lend you one too.

A bit intimidating at first but not too hard to deal with. Putting the whole thing back together is easy with a staple gun. Particularly a long nose one. See for instance https://pinside.com/pinball/forum/topic/lotr-refresh#post-3209959.

You should be able to get them out without damage. Gently tap them from the top with some protection around so you don't mistakenly end up messing up the top of the playfield. Once the bottom head separate a bit you probably can use some pliers to pull them out completely. Putting them back on a new clear coated playfield you'll need to be very careful. Probably want to re-pre-drill the hole on top so the clear don't pop out.

That's me but I'd stay away from the strippers (no pun intended!) and sand. You'll need to sand anyway to get a smooth surface.
I'd use a random orbital sander with a rough grit (80 or so) to get the most of out it and then switch to something finer. the cabinet is silk screened and there is no glue or vinyl involved so this should be quite straightforward. Sanding can be a pain (it clogs the sandpaper) when there is glue and vinyl but not here.

On the stickers take some detailed pictures of every single one. You can try steam. It may help detach them but they'll wrinkle. Worst case you can reprint them on brand new yellow paper.

On the rotisserie, I strongly recommend putting one together for the playfield repopulation. It takes 1 hour, probably cost $100 tops and saves you tons of time.
There is stuff that's just so much easier with the playfield out of the cabinet. Not to mention getting the playfield up and down in the brand new cabinet increases dramatically the risk of scratching the brand new sides of the cabinet.

I can't remember exactly how much I paid and it might have been closer to $200.

You can try both methods on the head and see how they compare. With the stripping agent, unless you use something super strong, you have to wait then clean up and then sand anyway. I'd actually be curious to see both methods side-by-side on the same game.

I've used Bondo and one problem is that it cures VERY hard. So if you don't sand soon, it ends up much harder than the surrounding wood which can be an issue with sanding something that's a bit thick. Except for that that's the way to go.

The smoother the surface the better the decal adhesion. It's the opposite of what you need for paint, clear or filler adhesion, where you need tooth for good adhesion. You'll need to prime and paint after sanding anyway and then possibly sand the paint if it has orange peel. Rattle cans of semi-gloss paint work great. Personally, I used a roller and Rust Oleum semi-gloss for the outside then lightly sanded it.

The wood filler works fine except for the edges, where you need something stronger. Since minor edge repair is usually needed, you're better off using one single product with no surprises - Bondo. I've never used fiber glass which is needed when you have more serious problems. On your game it does not look like you need it.

SM is my all time favorite game. The sound, the flow, the shots, the multipliers... The rules aren't difficult to understand, and the wizard mode is attainable.

I've used this before and it's strong. There is a "after wash fluid" that helps neutralize this toxic stuff after the paint has been removed.

Check this thread. Looks like the old art came right off.

https://pinside.com/pinball/forum/topic/potc-partial-restore

Glad you went the sanding way.

On the head back panel, a few years ago when I did my TZ resto, Steve in Escalon did the silk screen for me, but he was also offering pre-cut, pre-screened replacement panels for sale. Not sure if he still does and has them for Sterns but that's another possibility.