Alright, so I made everyone a simple translation guideline as to what's what, and a little description of how each part functions.
Wall-of-text guide for LZ RVTop case: simple, you pick the top case colour and how many.
Bot case: same as above, so basically you can mix and match colours.
Notes: I've seen all these colours in person.
Blue - really nice deep electric blue.
Silver - really nice shiny silver, great sheen, and bright.
Metal-gray - This is 100% gunmetal grey. You can't go wrong with this colour.
Black - Pure black, it's a very nice base colour, works with almost all keysets just like Metal-gray.
Plates: You get the choice of Alu for Aluminum or STS for Stainless Steel.
Notes: Alu is very nice for tactile or clicky switches. It's a lot more flexible than steel, which is a GREAT thing. It gives you that really comfortable bouncey-soft-cushioning feel with tactile/clicky switches.
You could also use Alu plate for linear switches with very light springs for bottoming out, and it'd be a really nice "typing on clouds" clacking experience. It's really personal preference, but I'll try to describe the differences.
Steel is a no-brainer for linear switches. For linear switches, you want to eliminate as much flex and wobble as you can for the smoothest feeling. You could also use steel for tactile or clicky switches, but I found that the lack of flex made it feel a little harsh when bottoming out (fingers get "shocked" and hurt a little over time), just my personal preference.
Finish wise, steel would be cleanly cut and lightly finished, and aluminum will be anodized silver, usually.
PCB - you get a choice of quantity, and they come default with a USB Mini connector. Micro is an option, but you have to make a note. Personally prefer Mini, because it's more widely used, and compatible, also easy to plug in without looking at it.
RGB LED / SMD (extra cost, should be below in "additional options") - These are surface mounted RGB LEDs that are to be soldered on the bottom (side) of the PCB, facing the desk. (Additional cost, but it's a really nice effect with the acrylic plate insert).
Additional options:You get 1 of each option above in the base price of the GB, but if you wanted additional plates or PCBs, or even keyboard assembly parts, this would be the place to order it.
Additional plate - self-explanatory
Additional PCB - same as above
Additional RGB LEDs (SMD type) - I believe you get enough for 1 PCB with a set of 20.
Diodes (SMD type) and
Resistors (SMD type) - Usually the PCB does not come with these, and you'd want to order them.
Switch film - These are thin non-sticky films that go between the top and bottom switch housing, similar to switch stickers, but better since they do not attract dust.
Cherry stabilizers - your choice of 6.25x or 7x set
Acrylic plates - This requires a bit of explanation.
The acrylic plates are usually sandwiched between the TOP and BOT case housing, to allow the RGB LED lights on the bottom of the PCB to shine through. You could order RGB LEDs, but without the acrylic plate, the effect will be lost. The plate is a must have if you're going with the RGB LED route.
Workshop assembling commission - This is basically an assembly option for your keyboard, the whole thing. There is no set package or price, and you will have to comment on what exactly you want soldered, such as, Assemble: 1x PCB with MX blues (you would have to buy or send some switches over), in Winkeyless, soldering for switches, diodes, resistors, switch LEDs, back SMD RGB LEDs, etc etc. You could also specify switch tuning, be specific, if you want switch films, lube, spring swap, etc. Of course, the price varies, so it could get expensive, but is a very convenient option, as LZ does good work.
I hope this helps!