The main problem, of course, is that Barnabas, Julia and Eliot radically changed history. Originally, Edith's (and, hence, Gabriel's) children were the heirs, but now it's Quentin I's son, Tad, who has become the heir and all future generations would be passed down through that lineage. Therefore, no Elizabeth or Roger, Carolyn or David (at least living in Collinwood). When I did my Charles-Delaware-Trollish version of continuing the series, I did just that: when Barnabas, Julia and Eliot return to the present day (1971), they find an entirely different Collins family living there. Whoopsadasie! Now how do they get out of that pickle? (And the subplot dealt with another problem: Barnabas used the I-Ching to travel to the past, sending his astral-self to 1840 to possess his own body. He returned to the present in that body. So what happened to his body sitting in a comatose spell? Won't there be two of them back in '71? Another uh-oh.) But in true DS spirit, I managed to get them out of another fine mess they got themselves into.
Gerard