I'm afraid this individual cannot be the Ira of Lake Pleasant. This individual's name is actually Ara rather than Ira. In the entry for the children of Asahel he is shown as Ira, but in his own entry "Churchill Family in America" shows him as Ara and says that the name was given erroneously in the earlier entry. One of his sons was named Ara Dan. More than that, Ara and his wife Sarah moved to Batavia in the same year they were married, 1809. Batavia is in far western New York and was an area where numerous Connecticut Churchills settled. The family remained there, with their children all being born in Batavia or nearby Alexander.
I have fallen rather behind so have not had time to check the Iras in "Churchill Family in America" (CFA) to see if any of them might be the individual from Lake Pleasant. There were Connecticut Churchills who settled in Boonville, New York, and in the Black River Country and Watertown. Both areas are west of Hamilton County. Their moves were long before 1845, and by 1845 the majority of Churchills from these areas were moving again, mostly westwards to Batavia or beyond. Thus, while there could be a son or grandson named Ira in one of these families who either was not well documented or whose name was not reported to the compilers of CFA and who found his way to Lake Pleasant in 1845, the likelihood is that the Lake Pleasant Ira Churchill was not a Connecticut Churchill.