Both of the John Gleesons you have listed went by the nickname '''Fira''.
Nicknames were commonly adopted amongst the Gleeson (and other families,. e.g. Ryan) in North Tipperary parishes, such as Silvermines. See also 'Using nicknames in Irish research' (2012), ''Descent'' (Society of Australian Genealogists journal), Vol. 42. Pt 3. September 2012.