Of these, the only one that isn't well known is Nitrogen. The Nitrogen levels at Mars are somewhat unknown, but expected to be pretty low overall. Of course, Nitrogen isn't required for a colony of what you have.
The one thing that actually takes area is to grow food, which you did not include. On Earth, growing crops requires about 1 acre of land per person per year. I believe Mars habitats would be closely monitored in temperature, and have less meat, which would increase the yield by a factor of two. More intense methods could make that to a single acre, as is discussed at World BuildingWorld Building. In fact, it could be much less than this, but...
In The Martian, assuming a 2500 calorie diet of pure potatoes requires about 370 m^2 of land. Let's increase that to 500 m^2 to allow for other types of crops to be grown to give at least some variety. That also gives about 1 acre of land (4046 m^2) feeding 7 people So far so good, 4000 m^2 of farmland would be the minimal required.
Beyond this, the shelter could in theory be below the farmland and be just fine. Give, say, 500 m^2 for stuff on the surface, and one would be more than fine. Let's even round up, and say that about 700 m^2 of land is required per astronaut.
Fuel for the return would come from the atmosphere. The amount of regolith required to make the water would vary depending on where you land, but might require some significant investment. If you are planning on purely solar powered operations, an area of 6600 m^2 of panels would be required to give 100 kWe of power. Nuclear is highly recommended, not only because it is more dense power wise, but also produces waste heat, which can be used for heating the habitats.