Perhaps the writers are unaware of how Mrs. Johnson originally came to work at Collinwood as they weren't around at the time.  They must have presumed she was working there at an early age.

Has Kate Jackson ever been interviewed on the DVDs?

When did Violet Welles pass away?

Who did the closing "Dark Shadows has been a Dan Curtis Production"?  That's the first time in almost three years!

So, there are three sets of cousins: Liz & Roger, Quentin, Chris & Amy.  I can see Jamison as Liz and Rogers father, 1897 Quentin's son as Quentin's father, perhaps a second son of 1897 Quentin as Chris & Amy's father?

Apparently in PT, Portia Fitsimmons had a huge impact on Sam's career!

1897 Laura Collins is unique in many ways but one is that she was there with the pre-cursed Collins family of the 1780's, and Barnabas is the one other character who can actually make that claim. 

[spoiler]When she returns from Egypt she has a unique perspective comparing the grim, despair state of the current family as opposed to the content, normal family she probably left behind over a hundred years before. 

...Possibly wondering why Jeremiah took over a decade to marry again and both he and his wife dying so soon after and then almost the entire family she knew after that.

...Joshua managed to build the larger house on the hill he always talked about, telling people he expected a larger family (with Jeremiah, Sarah, & Barnabas and their families being too crowded for the former mansion) though she suspected it was to better look down at the common townsfolk. 

...Moving into this new house seems to have brought a curse as the family experienced tragedy immediately afterwards and continuing to the present.[/spoiler]

They could have used this to start a romance between Julia and Professor Stokes.