Widow was Elizabeth, probably b abt 1776, lived to at least 1836. I've identifed 4 children:
John A b abt 1795 - 1870 or aft, m Mary H unknown
Anna A b 9 Mar 1796, m Elijah SHOEMAKER
Margaret b abt 1801
Agnes b abt 1805 m James (Jacobus) SHOEMAKER

Yes, Elijah and James were brothers, sons of Isaac Shoemaker and Mary SWARTWOUT. They came from Delaware Twp, old Northampton Co, PA.

I don't know where in NY McKey came from. During the Revolution I think he served from Ulster County NY. On 1880 census daughter Agnes stated that both her parents were from Scotland but I dunno about that - she may have meant New Scotland, Albany Co. I don't know where those children were born or if there were more, which is likely enough.