Additional founding leaders in U.S. rec tree climbing in no particular order:
Elliot Su (Taiwan)
Sophia Sparks (New Tribe principal)
Patrick Dimmer (early innovator in accessible tree climbing for physically impaired climbers)
The TCC "Who's Who" page
that you looked at has more info on the folks in the list above.
I'm sure I've missed a few, the above list is a good start on the rec tree climbing founders and next generation founders anyway.
Other notables who've influenced rec climbers:
Richard Preston (The Wild Trees author)
Dr. Steve Sillett (PNW tall tree researcher)
Marie Antoine (PNW tall tree researcher)
Michael Taylor (PNW tall tree explorer)
Dr. Meg Lowman (tropical canopy researcher)
Many more notables I'm sure, these are folks who've inspired me and many others