Two here.

Anyone know the name or part number for that little red tube diffuser that goes over the bulb under the ramp return, near the shooter lane?

Yes! Thanks so much. Mine is really faded, those look nice & bright red.

Pretty sure it's factory:
FP2.jpeg

Is that the wire one-way gate?

My FPII backglass had a mix of warm & cool frosted white 1-SMD, Pinball Life "Ablaze" brand. Didn't seem too bright to me and I'm pretty sensitive to that stuff. There's a lot of masking area, helps keep the overall brightness down. I've heard people recommend using those cheap old flat-top style frosted LEDs. They kinda suck on playfields, but great for turning down backglass brightness.

It's easier on later balls since letters carry over. For example, if you start ball 2 missing one letter, you just need to complete that one letter and spell it twice more to get credit for three completions on a single ball. Also a good thing to focus on in multiball.

Four.

Edit: nope, turns out it's one.

Oops, good catch! FPII was the last Williams game with one high score. Laser Cue was next, first game with four high scores. I used to have them side-by-side, got 'em mixed up.

To be honest I rarely try to shoot the ramp. Not really worth the trouble unless it's lit for extra ball. But I definitely shoot it from the right. Not a feasible backhand unless you get lucky and smack it on the fly.

Rip that lit spinner! Especially during multiball for 2x.