Firstly, no idea about Michael Bingham Kelly - that link doesn't work that you sent. What dates are there for him?
Secondly, I am not sure of Anthony Kelly's origins. Given these dates it is possible Edward was his grandfather, or a great-uncle, the records simply don't help us due to lack of documentation apparently. There aren't an enormous amount of Kellys either, so that going back a few hundred years a common ancestry is likely. I read an old Belmullet history book that confirms the O'Kelly Clan arrived from Roscommon and Galway into Belmullet. They previously held lands in Roscommon and Galway since the Middle Ages - and fought in the 15th century against the O'Donnell family of Donegal, in alliance with Mayo Burkes.