1. yes
2. Card back first, then any card that is not standard. Aces are a good idea if they have a date code on them. They are most likely of all cards except joker to be customized. If the Ace of spades is ordinary, then any unusual joker, etc. If everything is pretty normal, just submit the back.
3. I do, but only for decks from Aruba casinos, or the occasional deck that means something to me. I have a lot of Aruba traders and 10-20 other traders.
4. This question just came up amongst the Chip Guide admins. We are trying to customize the fields for other collectibles, and right now, we are focused on playing cards. This is the list I gave as a start:

manufacturer
back design
base color
other colors
date code - mostly useful for USPS cards
border (standard/faded/no)
stingers - designs added to the corners of back designs to avoid flashing cards (yes/no)
tech art/no peek 21 - black blocks or face card letters, JQKA, in the corners, so they can check for blackjack without revealing the cards (yes/no)

If you know the date they were made, the date they were taken from the casino, or even the date used (they used to write it on boxes), then I would include that as well. Another admin makes note of the type of box - no window, small window, full window.

Whatever makes you happy, really. I hope this helps.

Michael Siskin