Bacteria, Lichen and Moss may not cut it.
The article presents a model for terraforming Mars. They would use a progression from microbes to lichen to moss in order to produce oxygen.
Surface vegetation only accounts for about 10% of the free oxygen produced on Earth. The other 90% comes from phytoplankton in our oceans.
Here's a goofy idea: after they warm the planet and release the water then have geneticist engineer a bio-foam with the goal of having the largest possible volume and surface area?
Who knows, by the time they start thinking seriously about making Mars livable, they may have the technology.