So much of this makes sense and is close to what I had envisioned in the unchanged (non-Barnabas) past. I had some differences. Rachel Drummond, of course, would not have died. She would've remained on as the governess to Jamison and Nora. I also believed that Quentin's siblings (meaning Judith and Edward - Carl was sent away by Judith) either killed him and blocked his body up, or, with (or maybe without) Quentin's cooperation, blocked him up and left him a gun with one silver bullet. Beth committed suicide (like the governess and companion of Quint in The Turn of the Screw). Of course, that leaves some unfinished business, such as Laura returning, Magda trying to find a cure when she found out she, well, shot herself in the foot regarding Crazy Jenny's children (and what about Crazy Jenny? - I figured she just expired sadly and in loneliness locked away) and would there ever had been a Petofi? Regarding Laura, maybe Edward and Judith found a way to stop her (as she was stopped in modern time without the help of Barnabas). As for Magda trying to repair things, maybe big bro and sis "took care of the problem" before she could do anything and she and Sandor moved on looking for another wealthy family to dupe.
Gerard