1.) Jazz (Fiesta Powershift has more lag). But at high speed, even-stevens.
2.) Focus. INCREDIBLE suspension.
3.) Focus or Fiesta. Hmmm... great leather on the Fiesta.
4.) Depends on your priorities. Personally, I'm okay with buying a Jazz.

5.) Focus or Jazz. The Lancer's rear seat isn't that great considering its size, and the suspension limits trunk space. The Focus has a great lot of space and a huge trunk, BUT... the Jazz has better rear headroom.
6.) Jazz. Hands down.
7.) Hard to say. The Powershift makes for good cruising economy, but the Lancer MX is light for a compact car and the Jazz is the lightest of this lot. Many people have been disappointed that the new Jazz can't match the old one, but it's still decent in traffic. In my experience, the Fiesta 1.6 can get similar. On the highway, the Focus's Powershift and good aerodynamics make it near as economical as the smaller cars, though in traffic, the weight will probably cause it to be less economical than the Lancer.