Franchfarran Legion
Right, let's get things off to a start...
Who the Hell are these guys?
The Franchfarran Legion are, simply, the French Foreign Legion in Space, hence the stupid name. They don't have a home planet, but mainly like fighting in Jungles, Swamps and other dangerous terrain-y hoo-ha. They are all failiures from other guard legions, who somehow weren't BLAMMED, and decided to try to die in a glorious death for the Emperor. They hate stealth, so wear bright red and green armour.
So do they have tactics?
As they are a T\G legion, not really. Although they live by the obvious tactic of "CHUCK MORE MEN AT IT!" and occasionly have Baneblades, they do not have any more tanks AT ALL. They suffer from hating plasma weapons, so they only use grenade lauchers and their trusty ol' flashlights. They have even resorted to using Techpriests as actual troops.
How are they alive?
No one flipping knows anymore. The Imperium doesn't like to say they exist, and even order the Imperium's Pride and Joy to fight them. Things never go to well for the Franchfarran Legion...
Models?
Just use Cadians. Use the Catachan Command Squad though.