Hey, Brad!
Since I was working at Slate Run Tackle back in the later '80's I can tell you that the Soft Hackle Emergers tied in that style were originated by Nick Nicklas. Nick is originally from Woolrich, PA and had moved out west. He guides for Blue Ribbon Flies. Back then he would come back east and tie and guide for Slate Run in the early season until Memorial Day; then, he would head back out west to live and guide. I believe he also guides for saltwater out of Texas part of the year. He no longer comes east.
Some may be under an erroneous impression that another local tier originated these patterns. That would be wrong. Even though a pattern or two or variations thereof are available in another shop these patterns were copied/varied later and made available.