Interesting. Maybe the McKees and Weir families were close and had a couple of different intermarriages? I have John McKee purchasing property on the James River in Virginia in 1752 and dying in Rockbridge in 1792. His daughter Mary Bean was born in 1742 in Augusta/Rockbridge County and married Hugh Weir there in 1770. Hugh may have served in the Cumberland, Pennsylvania militia ca 1758.
Both John McKee and Hugh Weir were born in Antrim County, Ireland. Hugh was born in the town of Enniskillen.
Were your McKees and Weirs from that same area? Where did they settle?