Isn't this just crazy! I love it. Very nice to meet you and I would love to help you both out. Where did Rebecca Jane Flanary live when she hid out Dick Yaeger and when was this? The reason I asked was that The James/Yeager gang robbed the bank in Corydon, Iowa in the period just after the break up of Quantrille's Raiders. Does this make any connections?
On another thought trail, my research says that the early Quantrille gang went down into Texas, this is before the raid on Lawrence, KS, and this could have been when they hooked up with your "James Littleton of Texas". Now we just need to get him connected to your Great Grandmother. If you want to communicate directly, feel free to drop me a line at rhamel@westmont.edu.