I am related to the McElhinny family in Pa.I know I saw those names you mentioned before.My family came from Jefferson Township, then to Mifflin Township, Pa.I'm not sure if we are related but I found those names under Jefferson Township.
"History of Allegheny County Pennsylvania"
in Two Parts
Chicago, Ill. A. Warner & Co., Publishers, 1889
(can be found on the internet - under digital History of Allegheny County Pa
Under Townships Chapter VII Mifflin (Homestead) - Jefferson (West Elizabeth)
Under Jefferson Township, pg. 78
"The names are remembered of the following residents prior to 1830:
James and Jesse Lobb...McElheney and sons Robert, Samuel, David, Holdship and James..."
I hope this helps you a little bit.
P.S.I am descended from John H. McElhinney and Jane Rath.