Hi, Patti--welcome back! I can answer your OS questions at least.
OS Angelique's curse was that whoever loved Barnabas would die and that he would live with it for all eternity. Angelique was amoral to start with, and was increasingly desperate because everything else she had done to force Barnabas to love her hadn't worked. She stuck pins into a Sarah doll to make her sick enough that Barn, not knowing it was a hex, promised to marry Angelique if she cured his cherished little sister. Angelique took out the pins, Sarah was cured, Barn married Angelique, and we know what happened next. But Sarah really sealed her fate when she was dying after seeing what her big brother had become. (She went into shock and died of pneumonia.) While Barnabas held her, her last words were, "I love you, Barnabas. I always will."
Roger was the last one out the door when the family abandoned Collinwood to Quentin the angry ghost. On the doorstep, Roger shook his fist and vowed that they would be back. Of course, the next thing we know, we hear Quentin's uproarious laughter echoing throughout the empty, deserted, darkened house.
In the OS, Barnabas and Sarah--and their parents--all were born in America, because the Collinses had come over in the late 1600s and built the Old House atop Widows Hill. I think that early in the movie, we have a shot of the boy Barnabas turning to look at the girl Angelique as he and his parents embark on a ship to America (from Liverpool, maybe?). I think Barn and his parents traveled in whatever was first class in the 1700s, whereas Angelique and her mother were in steerage on the same ship. So in the movie, only Sarah--if she was in the movie at all--was born in America.
Johnny Lee Miller was movie Roger and now plays the title role in "Sherlock." If you want to see more of him in a very different role, check out the 2009 BBC miniseries of Jane Austen's "Emma," in which he played Mr. Knightley.
I don't remember who played Vicki or Carolyn in the movie (which I'm afraid I hated), but Gulliver McGrath played David.
No idea why they made movie Roger such a jerk. I guess they were just amping up OS Roger for the big screen. Don't remember the paintings in the basement, I'm afraid.
Anyway, I hope some of this helps!