We will begin by going to some expert information. This is an excellent project in which to be engaged, and we want to encourage your project as much as we can. So, begin with our How-To Articles on Recreating the Prairie and Meadow Gardening. The meadow garden can be mixed in with the prairie to enlarge the habitat, attract pollinators and enhance the attractiveness of the area. Both of these articles are full of detail and include bibliographies of books with even more information.
After you have read both of these articles, anything else we might have to say could be redundant, but we will try to address your individual questions. "Soil chemistry" and "biota" are not terms that ordinarily roll off our tongues, so we will refer you to this article from the University of Massachusetts at Amherst article on Chemical Properties of Soil. As you probably know, Mr. Smarty Plants does not know everything, so we looked up "biota" and found this definition: "The combined flora and fauna of a region."
To sum up our understanding of your question, the choices we have of soil are alkaline and acidic. If those change, it will be over millenia. In the Austin area, our soils are underlaid with limestone and therefore alkaline. In East Texas and other forested areas, centuries of dropping pine needles and oak leaves, as well as other organic by-products of plants, support an acidic soil. Some soils are actually circumneutral, which allow for a wider range of diversity in plantings. The other types of choices in soil we have concerns texture - either clay, which is very dense and drains poorly, or sand, with very large particles which drains readily. Again, in this area most soils are clay. Neither of those are going to change readily. Biota, which involves plants, birds, insects, pollinators, snakes, and animals, including us, may certainly increase in a healthy vibrant prairie, but probably won't change much.
We suggest you begin by finding out exactly what kind of soils you have. Go to the Texas A&M Agrilife Extension site for Travis County for their article "The Real Dirt on Austin Area Soils." This includes information on how to contact the office and to get a soil test done on the property concerned.
Next, go to our Native Plant Database, where you can search online for plants native to North America. Since your specific concern is Little Bluestem, we will go to the database and search for that plant using the common name of Little Bluestem. Once there, we will find our webpage on Schizachyrium scoparium (Little bluestem). If you follow the link to that webpage, you will learn its growing conditions:
Water Use: Low
Light Requirement: Sun , Part Shade
Soil Moisture: Dry
CaCO3 Tolerance: High
Drought Tolerance: High
Soil Description: Well-drained soil. Sandy, Sandy Loam, Medium Loam, Clay Loam, Clay, Limestone-based
Conditions Comments: Little bluestem is wonderful planted en masse. The visual dynamics it provides range from blue-green in late summer to golden with cotton-tufted seedheads in winter. It readily reseeds so little bluestem is not recommended for small gardens. Little bluestem is tolerant of a wide range of soils but will not tolerate wetlands or sub-irrigated sites."
On that page, you can go down to the bottom to find the link to the USDA Plant Profile on it; clicking on the state of Texas (which is green, meaning that plant grows natively in that state, you will get this county map and learn that it is native to Travis County. Go back to the webpage and click on the link to Google for that plant. From that list of reference materials we selected this one from the USDA Forest Service, which probably has way more information than you ever wanted.
Again, on the original webpage on Schizachyrium scoparium (Little bluestem) you will find a Bibliography, links to archival information, etc. With all that information, you should compare growing conditions with the area where you are attempting to establish your prairie and see what, if anything, needs adjustment, or even use of a different grass, which you can probably find in our database.
Our prescription: flexibility and patience.