Also based on the name of johns eldest son I am going to hazard a guess that Johns father was either a Michael or a John. And you will find both names on the griffiths valuation in 1855. I think Michael was older as I haven’t been able to find a death certificate for him meaning he died before 1863 but after 1855. This could indeed by your Johns father, or his brother. The John on the griffiths valuation of 1855 seems to be a bit younger and possibly too young to be your johns father.
Also note when looking at the griffiths valuation that they often have lots of records for the same name so a few plots for John, Martin, William, Michael and so forth. These are not different people. If you look at the original records of the griffiths it will tell you what is on the plot ie a house. You will find that there is usually one plot with a house and the rest of the plots of the same name are just land plots. When you study the ordinance survey maps you will see that there plots are actually together and the houses are grouped together. It helps if you learn what the letters mean in the original documents so you can find the plot on the maps - ask ireland.com is really good for this as it allows you to look at old maps and modern maps. Specifically however on Taughmaconnell townland there is a William, Michael and John. On coolfree and camla there is Martin craven (my ancestor). He has 2 plots one with house on coolfree and land on camla (or other way round) but they are next to each other. We also have a William and James living on cuilfadda townland. This is in 1855. All these townlands are in the parish of Taughmaconnell.