well, I think you're reversing cause and effect - I think the Byas we're hearing in 1944-1946 is, at this stage, reacting to the boppers - hence the slight modernization of his sound. Lucky Thompson also first recorded early 40s (I think, or maybe 1939), with Jonah Jones (Commordore I think) and he is also, at this point, primarily a swing tenor, but than a few years later is changed by the modernists - but neither was, out of the gate, a modernist. If we had to pick one, I would say Dexter Gordon, though (and I don't want to start a separate fire storm here) I never found his playing very compelling at any period - given the Savoy recordings, maybe the first bebop tenor player was Bird -