Bringing an old idea back up, for one of the rangers:
Venerable Dragonwrought jungle kobold Paladin of freedom 8/Purple dragon knight 2/War chanter 10
Feats: Leadership or Dragon Cohort
Cohort: ??/kensai 10
Have the kensai transfer 10 points of his BAB to the kobold, then have the kobold use the war chanter's 10th-level ability to allow all nearby allies to use the BAB of their best member.
Everyone, including the kensai, now has +30 BAB at 20th level. The paladin levels can be switched for anything with good BAB.
As for flight, how light can you make everyone? Can you fit them on a capret of flying?