I know a biologist in a cannabis R&D lab and I forwarded your question. The simplest answer is... You want as much variety as possible. You would not necessarily worry about microbes out-competing each other or not being compatible. Give me a little more detail on what your end-goal is and I can get you more detailed information.
Are you looking for microbes to make available nutrients to the roots? Are you looking for microbes to fight fungal pathogens? Are you looking for microbes to attack pests? (ex. Botaniguard Maxx Mycoinsecticide https://www.bioworksinc.com/products...igard-maxx.php - Beauveria bassiana )
As you are likely aware - most commercial products (ex. TerraGrow https://www.biosafesystems.com/terragrow/
) are combinations of microbes that have been developed to be compatible with each other. Do you want to pick and choose microbe species individually to compose your own combo solution?