How do you join the group buy? Is it just for the kits or can you order a pre-assembled keyboard?
Can you get standard qwerty key caps?
I checked out their website and I see for $50 they will assemble it for you but their customer
service said they don't deal in the actual keyboard parts i.e. the key caps.
The Group buy is for the DIY kit, but massdrop has recently added an assembly option, where they'll put it together for you. I don't know much about it though. There are several GH'ers (including myself) who are willing to assemble one for you.
To get in on the GB, you have to sign up for massdrop, then when it's available, commit to buying at your preferred price (thus far, it's gone to the best price tier every time) When the "drop" is done, they charge everyone and order everything, then ship it to you.
"QWERTY" isn't really a standard, so there really aren't any "standard qwerty key caps". Perhaps the most common layouts for qwerty keyboards sometimes have group buys for them, but the ergodox is fundamentally different. You can add many of the qwerty keycaps from places to it, but most of the modifiers and the thumb-key area will need either blank keys or special keys. There was a group buy for a keycap set (called retro DSA) a while ago that I have on my ergoDOX. I was able to order a lot of keys in the sizes I wanted. Also massdrop has had at least two group buys for blank pbt keycaps.
One issue is that the ergodox is fully programmable, You can put on it any layout you want, so having a group buy for non-blank keys isn't usually a workable idea, since everyone has their own layout that works for them. You can use a configuration tool on massdrop's website to make a new layout with up to ten layers. I plan to have layers for dvorak, qwerty (for when I have dvorak set in the software) and gaming on mine.
I think their assembly is only to assemble the kit. You will have to add your own keycaps.
Hope this helps!