I don't like table linens on un set tables this looks like a beautiful table don't cover it up. as for centrepiece In this case maybe one table runner and a beautiful bowl of fruit and a couple of lovely candle sticks I would move the pieces you have there now to the window sill they will really pop there.

I believe fresh flowers or fruit centerpieces were the standard in the era.

How about a large oval basket or wooden bowl as your centerpiece? You can fill with both green and red apples, or lemons, or even artichokes. The artichokes have your green and purple hues.

I found an artichoke centerpiece on houzz!

I'd find a large flat ceramic bowl by Weller or Van Briggle (or Grueby if you've deep pockets or Roseville if you like multicolor ceramics) or noname potteryRUS in that robin's egg blue/green color that was so popular a hundred years ago. Just like it is now. I'd fill it with fruit or pinecones, or Christmas ornamnents...just depends on my mood.