In parallel time Barnabas and Josette married and had children (one of them Bramwell.)
If Trask hadn't shot Angelique in 1840, she and Barnabas might have decided to remain there and live out their lives as normal human beings. Their decendants could have been the basis of an entirely new branch of the family (which is why 1841 parallel time was so unecessary; the whole 1840 story line virtually wiped out the 1897 history and characters). Leticia and Desmond could also have been the predecessors of the "new" Collins family that Julia and Professor Stokes should have found upon returning to 1971 from their 1840 adventures.
When Roger scoffed at the notion of Amy and David playing with toy soldiers it made me wonder about Roger as a child.
Wouldn't it have been great, if the show had lasted, if they had gotten around to doing a story line in the roaring 20's, when Roger and Elizabeth were still children? It would have been hilarious to see "little Roger" already pompous and egocentric, and "little Liz" acting superior and snooty.
Charity might have married and produced an offspring that married someone named Peterson in the 1920's, hence the Trask-Peterson connection. Lots of other loose connections could have been tied up here as well. Quentin's daughter Lenore would have been an adult (and a flapper!) by the 1920's and married someone named Haskell or Jennings, for instance. Grayson Hall could have played a DuPres cousin who fell in love with a man named Hoffman.