A: We do say 2-6 players on the box, but there’s no reason seven couldn’t play! We’ve seen even larger groups play Fluxx with no problem. It just means there’s a bit longer wait for your turn to come around, and it’s a little harder to squeeze everyone around the same table.
However, combining decks isn’t really necessary as far as increasing the number of players. Yes, combining different versions does give you more cards, but that’s not really needed – one deck is plenty big even for eight. Instead, combining decks makes things more complex, and also makes the game longer. While it can certainly be done, that’s not necessarily what you’re looking for, and we don’t suggest it for new players.