I see this post is old, but I hope you see it.
I am descended from Micajah Butler and Mary Ann Brown!
YES, I heavily suspect Robert to be the father of John Butler. This Robert is the one with Will of 1795.
I now have records Proving relationship between Asa Denby, his mother Elizabeth Denby, and Robert Butler. Asa Denby is living BESIDE Micajah Butler in 1800!
If you see this, we need to talk!