Surely we have the ability, we just don’t operate on the timescale required nor would want to invest the amount of resources required. We make significant manipulations of our own ecosystem accidentally all the time.
We do if there exist microorganisms on Earth that can survive and multiply in the atmosphere of Venus. (The upper layers aren't nearly as harsh an environment as at ground-level, though I don't know if it's survivable by anything Earth-native.)
It has water (according to wikipedia), just not very much in comparison to the Earth.
In theory, some hypothetical life form could convert sulfuric acid to water, but I have no idea if such a thing is possible or currently exists on Earth.
> The concentration of water vapor (a greenhouse gas) varies significantly from around 10 ppm by volume in the coldest portions of the atmosphere to as much as 5% by volume in hot, humid air masses, and concentrations of other atmospheric gases are typically quoted in terms of dry air (without water vapor).
