Amanda really didn't work in 1897, she broke up the pacing of the story with Quentin, Beth and Angelique. I have no doubt with Angelique in the picture Beth could've been driven to the edge and beyond without Amanada around.
I love 1897, and have often thought how the Leviathons would work in that time period.
I have read a fan fic with Barnabas vs the Leviathons in the 1870s which was great but wasn't finished.
Amanda/Olive worked a lot better in the modern day as Quentin's lost other half, another immortal he could've shared eternity with, and a connection to his past.