Starfleet and the Federation has always been a prime factor in Star Trek. To have a trek TV show that had no Starfleet personnel is too far outside the scope of Trek, I think.
We have seen examples of non-Starfleet investigation teams before.
Seven of Nine's parent aboard the Raven.
Professor Robert Crater and his wife, in Man Trap, seemed to be a independent archaeologists.
Janice Lester didn't appear to be working for Starfleet.
John Gill was Federation, but not Starfleet. The same with Worf's brother, however a non-governmental team sponsored out of say a university could be doing similar research on a planet's culture.