I'm one of those you contacted on rpol. Looking at the characters you already have, there are two characters I would like to put forth as potential characters to join the group:
Deerbrook, the Graceful Glaive who Fights with Panache. (Could easily be made into a Jack.)
Wisco, the Tough Nano who Lives in the Wilderness.
If it would help, I do have two other character ideas who would be fun:
Finnian MacKorm, the Tough Glaive who Rages
Zeth'ian, the Clever Nano who Murders (could be changed to Jack easily)