With 3 pins available it is possible to get 6 switches by charlieplexing. It is prone to ghosting, though.

Since one of the pins I have available (P2) is biased to ground I was able to get only 4 without ghosting.

On the table below Z represents input with a pullup.

Next challenge is to add a pot slider to this cauldron ans stir while spelling some witchery....