Deck of Every Card spades puzzle

Getting an X of Spades card from Deck of Every Card yields a string of letters (letter count equals X).

For new players, the string is a subset of the common string "UJLWTTLEJCCQYOIYMWESZWPWFOBUNKWGULYKDQNADDBWXUWKRRRTBIHXBUMWAIZGEDTHJGGUGEWCCCICOPJTNM". It is coded with the Vigenère cipher, the key is "ABCDEFGHIJKLMNOPQRSTUVWXYZ". The decyphered string reads "THIS ONE WAS RELATIVELY EASY GO ASK GRANDPA SEA MONKEE ABOUT STAGE TWO FOR YOUR PERSONALIZED CHALLENGE", without spaces.

After a player asks Grandpa about "stage two" the cards start giving subsets of some different string. The new string is different for each player, but the same for the same player. It is coded with the Playfair cipher, the key is the player's name. The decyphered string reads "GREAT WORK YOU ARE READY FOR YOUR FINAL CHALLENGE ASK ABOUT ??????????? FOR THE LAST STAGE BE SURE TO DESTROY WHEN YOU ARE DONE READING", without spaces, where ??????????? is replaced by an user-specific password. The password is a 11-letter long English word (such as "copywriters").

Notes

• The stage one was decoded on Jul 6, 2015, at that time only the first 3 letters of the cyphertext were unknown.
• The stage two was publicly decoded on Jul 13, 2015.
• You need to unlock the stage two only once.
• You don't need to draw any cards or own the deck to unlock the stage two.