The Traveler also increased the moon's gravity. Since it could not increase the density( Nerf Density!) without serious consequences for Earth I suspect there is some quantum level stuff going on there, perhaps an increase in the theoretical graviton. That said terraforming the atmosphere of Venus would be a simple matter. The appropriate building blocks are there, just scrub the carbon, combine oxygen into the dual atom molecule we enjoy and that's that. The residual nitrogen and carbon dioxide would finish out the atmosphere. Solar radiation would be the next hurdle. We use lead as a radiation shield because of the number of electrons. In theory a dense enough cloud of electrons in the upper atmosphere would shield the planet from the worst of the radiation. This might also account for the orange sky of Venus, which if the atmosphere is Earth norm should be blue, as higher energy light frequencies are absorbed and only lower frequency red light gets through.

Terraforming ... You listed all the problems, just fix them. I'm more interested in how it made Mars inhabitable.

If a plant that was genetically modified to survive and reproduce in extreme heat and air pressure, it could potentially filter out the massive amounts of carbon dioxide in the atmosphere and take a step in making it habitable. #sciencebreh