Will you be adding another form of heat or reusing the vents for heat stoves? Will you be encapsulating any lead paint in such a way that the bricks could be covered, too?

Yes, we have central heating. We are building some walls to cover these in a few of the rooms, but in doing so we are losing square footage, so we hope to limit covering them up. I really want at least a couple fireplaces.

Here they've just used it as a feature. Romabio will custom blend masonry paint for you to paint them to match your walls.

Charming West Vancouver Cape Cod by McCabe Design & Interiors · More Info

Please don't tell me you've trashed all the original casing and baseboards.

What a wonderful feature to have in each room. I would leave them as is.

Unfortunately the previous owners replaced all of the trim/casings in the lower level. We are going to try to match it from the second story, budget permitting.

Amy, typically the lower floors & public areas would have nicer trim than the second floor. I would recommend using a taller baseboard and more details window trim than the second floor. For baseboards the minimum height is 1/2" per 1' of wall height. So a 10' high room should have at least a 5" baseboard, higher will look better. My entry hall is 11' and has 10" baseboard.

What are your plans for the ceiling?

You can put drywall over the brick and then install built-in shelves to make a built-in bookcase to make the extension look deliberate.

I have those same type fireplaces in my (much more modest) circa 1900 house. I wish there were a company that made vintage looking gas heaters like they showed in Downton Abbey in Carson's office. I ended up finding the slimmest gas fireplace I could find and attaching to the front of my fireplace.

Photo from the Downton Abbey exhibition: