Thanks for sharing Geoff, watch your syntax and your spelling!
I wouldn't say that Moncur *pushed* McLean into freer territories. McLean was already there, had arrived on his own strength with his Let Freedom Ring album, and was as much pushing himself as anyone else when he came back to freedom with One Step Beyond. "Stimulated" would be a better word I think. Similarly, I don't think Lee Morgan needed any pushing. The guy was a master of the trumpet and all over the map; this was recorded one month before the Sidewinder, just after Morgan had returned from an absence. Morgan seemed very much open for the new stuff being played at the time. This was before the success of the Sidewinder pigeonholed him.