Looks like this concept is a nonstarter.....for now.
Unfortunately credits are not transferrable at the moment and JDB has no plans to change it.
Since this game has advertisements and you can purchase credits, I believe this will happen at some time in the future. It just goes to reason that offering leagues with prizes or creating league where every season owners have to pay 50 credits to join and winner take all is the eventual evolution of this game.
Thanks for the feedback and I will continue to brainstorm and come up with new ideas to make my leagues super competitive and fun.