I cannot say anything official about hybrid AF working or not with non-STM lenses, but I have one clear experience with a third-party "Tamron SP 70-300 F/4-5.6 Di VC USD" lens, and this is awful:
In phase detect AF mode the lens needs 1-2 seconds to focus, in Live-View mode on the EOS 650D it takes 2-4 seconds, which is plainly slow. Especially above 200mm or with moving objects it has severe problems focusing at all in LiveView mode.
I often observe that the lens seeks its focus in the wrong direction first, focusing to the close end, then back to the far end when trying to re-focus on a distant landscape. It is my understanding that if it would use a hybrid AF then the camera should know at least sort of where the focus should be, instead of searching back and forth through the full range.
I therefore conclude in practice that either hybrid AF is not working with 3rd party lenses or that it is working too poor to even notice.