the 45 colt is not the parent to the 38-40 or the 44-40. close, but the 45 has a slightly larger base diameter and a slightly different rim thickness.
i have a few of each and wish they were a little closer. 38-40 and 44-40 brass are rare and a little tough to come by. Thanks to Starline though!
I think the 32-20 and 25-20 are closely related as is the 218 Bee.