All of those are only zero-sum if you pick a conserved metric. Land ownership is zero-sum if measured in square meters. But say someone buys up land that is parched, dead, and empty. They use it by planting moisture-retaining crops and windbreaks and growing food, or running a business of benefit to the community. Now overall everyone is a little better off, despite 0 square meters being created.

Influence is even more so -- it's common to have situations where nobody is truly paying attention to anyone else. The people with good ideas can't get any traction, and the whole organization just spins in circles, lurching from one externally-imposed crisis to the next. If the people who gain influence use that influence to promote others who are worth paying attention to (and thus they gain influence), everyone benefits. But if you measure that in terms of how many minutes each person gets to speak at the All Hands, it's zero-sum.

Yes, although we do measure it in square meters (or acres, or tatami mats).

Is there such a thing as "partially zero-sum"? I mean, to express how, unless you get really creative in difficult ways, the supply of land is under pressure due to other people taking all the currently useful parts of it, such as the parts on your island and not underwater.