There are at present no serious scientist working on these models. You have the odd fame - seeker like Zubrin and Fogg but no brilliant minds by a long shot. The guys and gals who are at the moment producing the long term atmospheric models of the earth could and should be applying that same technology to produce models of the Martian Atmospheric system under the influence of different factors reqiured for warming and thickening. David You seem to have the same notion that if there is a little water and atmosphere you have a usable plant. Mars from the outside seems like a plant that would be reasonably easy to tera-form.
Lets look at it more closely.
It is a reasonably assumption that Mars had an atmosphere much like earth millions of years ago and has lost it. From what it appears to have now is some condense water ice at its poles and some water ice perhaps in its substrata. The Volume of water ice and water barring rock is the key. This would mean space trucking water ice asteroids to the planet and delivering them to its surface. Why bother I ask.