You seem to know this already, but DON'T GET A BETTER/LIGHTER BIKE THAN YOUR WIFE!!
You're also aware of the WSD issue. If the bike doesn't fit, doesn't work "right", or doesn't look as cute as yours, chances are you will, sooner or later, loose your riding partner. Those bikes sound fine. We've got a couple of Trek mtn bikes, and I've got a Trek road bike. Have fun, and be careful.