Mars is believed to have lost most of its atmosphere because of the lack of a magnetic field, and also asteroid impacts. With a thicker atmosphere and a magnetic field Mars would be habitable. The temperatures on Venus aren't caused by the closer distance to the sun, it is entirely related to...
No I'm not "missing the point", it is possible to get two or more planets in that zone. Venus orbits at 0.72 AU, Earth at 1.00 AU, and Mars at 1.52 AU. It should be possible to have multiple lower mass planets orbiting at similar distances from 0.7 AU to 1.5 AU, orbital resonances could...
All of the planets should have individual orbits, and should be between the mass of Mercury and Mars. What can their orbits be in AU's? Is there a way to find out how close they can be without destabilizing each other? If we assume the star is about the same size as Sol.