6) How do the neon lenses work? I thought they just had a bevelled edge and refracted/reflected the VFD display, however I'm sure I've seen a photo with a blue face and red neon.

They simply have the edge from where the material had to be thinned down to fit behind the fascia - the areas that you actually see are thicker than the parts behind the black fascia.

Could you have seen a player with a blue face and red lighted buttons? IIRC there is such a picture about somewhere, probably from Tony Fabris...
The lighted button hack also improves the effect of the neon lense.

/Michael