what you say is all true. Som several agencies qnd agribusiness companies have sponsored research on agricultur methods on MArs.
The study o halophytes that can be used as food has developed loong lists of possible plants that ca be grown in very high salinity soils, including the Sulphates seen on Mars. I was amazed at reading about resaerch at U o Wisconsin for grains ; (barley millet ,quinoa,slicorn, saltwort (many others that we dont know much about but were used by ancient people ll over the world) VEGETABLES; Agave, beets, tomatoes (specific varieties like ROMA) dates, egg plnt, samfire weed,sea kale,rocket,jujube,tmarind, carob,FRUITS; marula , crnberries,sea blite , momgongo,FODDER AND GRASSES;acacia, alfalfa, bermuda grass, trefoil, salt marsh hay etc etc.
Itll be more an experiment on developing the vast areas that may be needed for growth using a fairly sterile media. Plants dont really need soil much of their respiration and nutrient uptake is via trqnspirqtion qnd chlorophyll production in the leaves. Soil is a holdfast, an provides mostly micronutrients except for grasses which convert the NOx into biomass.
Ill bet theyll be growing mushrooms and hogs.
U of Wisconsin won some prize for a habitat (surface model).Is built more like a thermos bottle with levels inside .I think some outfit is working on "Suburban development: beneath the martian "soil".