Leanor Proudfoot (Hitt) - Proof of these parents?

Leanor's two uncles, John and her grandfather Peter Hitt, were American soldiers in the Revolution."

So she's not a daughter of John Hitt, Sr.

That's a garbled sentence. John Hitt, Jr., of Fauquier County may have served in the Revolution, and Pvt. Peter Hitt certainly did.

Was she really born 1762?

The older brothers of Pvt. Peter were Elias & Charles.

This is what the phrase actually is from https://www.findagrave.com/memorial/40501184/leanor-proudfoot

Leanor Hitt, a native of Fauquier County, Va. and of German descent, married John Proudfoot of Scotland. Leanor's two uncles, John and Peter Hitt, were American soldiers in the Revolution.