Actually, I could see the Old House looking like that, since baroque/rococo was all the rage in the 1690'.
Yes, according to what I've tracked down on the Internet, the French Baroque style was popular through much of the 17th century, particularly the second half. Though one does have to wonder why an English family built a house in a French style, as was also the case with using Seaview for Collinwood on the original show. Though at least originally with the original show, the backstory for Collinwood was that Jeremiah had built Collinwood for his French bride, Josette - but, of course, that story went out the window once we actually saw 1795. But perhaps, had the pilot been picked up, the reason for the Old House being French Baroque would have been explained. Alas, as things are now, we most likely will never know...