I recall Leonard mentioned on the Yahoo group that he had Harry Riblett design the airfoil for this family of aircraft.
If you look at the coordinates you would see it's not perfectly flat, but close enough to call it flat. There was a big discussion a while back about people substituting other wings/airfoils to the LE family, and his response on 7/16/13 was "... I went to the trouble to get a Riblett airfoil that has a bunch of good qualities ... Leonard"
At Oshkosh last summer in his forum he told us it is a P2, short for pencil #2 lead, he laid it out and said that looks about right.
If your asking about the Legal Eagle I've gotta call BS.Clearly "borrowed" from the Mini-Max/Hi-Max/AirBike !Cant comment on the other designs.There are quite a number of differences in the Milholland airfoil and those you mentioned but then how many ways can a wing be built?You being a Noob, you should do a bit more investigation and learning before putting down the design every one here loves!