I'd vote for two 17' boats. The three week camping trips pretty much force that decision. The Honda Civic shouldn't be a problem--get a good roof rack. The 17 footer is a good choice for you. It might be a tad big for your wife, but you describe her as very athletic, so I don't think that will be a problem.

Personally I wouldn't built two of the same boat. Variety is the spice of life. If I had my heart set on the Artic Tern 17 I might make the second boat the CLC Chesapeake 16, which might be a better match for your smaller wife. Too bad there is no Artic Tern between 14' & 17'.

The diagonal of your living room is just over 21 feet. If you have to build in your living room, I'd build the boats one at a time on the diagonal. Is there any chance you can beg or borrow a temporary building space? Let us know where you are located, you might be suprised at what people have to offer. If you must build in you living space, please be careful about fumes and dust. Ventilate well. It won't be the first time a boat has been built in a living room. Do you have a boat storage space for after they're finished?