The historical articles on Francis Kinloch indicate that his wife, Mildred Walker, died in 1784. All the information we have on the children of Robert Chowning (my 4th great grandfather) would indicate that the Mildred Walker he married lived into the early 1800s. The final bit of proof that may be the most conclusive is that Eliza Kinloch d/o Francis Kinloch and his wife, Mildred Walker, inherited the Belvoir estate which was the home of her grandparents, Col. John Walker and his wife, Elizabeth Moore. If the same Mildred Walker had married both Kinloch and Chowning then the Chowning children would have also had a claim on the Belvoir estate but there is no evidence that they did.
I think that the Mildred Walker that married Robert Chowning is probably related in some way to the same Walker family as Col. John Walker and his wife, Elizabeth Moore, but is just not their daughter. I suspect that from some DNA identified cousins that claim a heritage from the Walker and Moore families.
Frances Marian (Fanny) Chowning did marry Jonathan Kemper. I have a scanned copy of the agreement to their marriage written by Jonathan's father Tilman Kemper attached to my tree on Ancestry. Francis Marion was a revolutionary war hero and I've run across multiple children named after him, both boys and girls with the feminine form of the name.