Fortune Cards have been a ‘swings and roundabouts’ aspect of D&D 4e, some people love them, some hate them. As The Sun Never Rises is a prequel adventure to the Encounters season, which does allow their use, the official line from the Drowathon team is that if you have fortune cards, you can use a 20 card deck following the standard construction rules.
If you are on Pedrs’ table, I have a set of 20 cards tailored for each character.