In an interview about Jeffrey Hunter, there was mention of a possibility of Jeff returning to the series. If that happens I see two ways for that.

1. Some time after Kelly ditched him, Jeff finally saw the error of his ways and became a better person, and will be attempting it make amends or peace with Zack and Kelly.

2. Jeff is still the same slime he was back in the day, and will have selfish intentions for the group.