I would modify the curve and ride that. I remember when I was first looking at folders, my LBS wouldn't even sell me a Swift when I told them I was using it for train commuting and getting in the office. In fact, the bike doesn't really fold. It just turns from a mostly horizontal bike to a mostly vertical bike.
It did ride well though, and has a great price point. So, you will probably be happy with a Curve and a Swift. Also, I believe the Curve has a Brompton-like attachment. So there you go. What is your partner using the Curve for? Can you steal it for train transport?
The stock tires that come with the bike are requisite for a comfy ride. Those, or Big Apples.