yes it's linked to the WL but the point is you shouldn't look at it like that. WL is the wave point of view (obviously...) and RF says photons are particles. A wave is everywhere, a quantum particle is somewhere with a certain probability. Huygens-Fresnel did not know about quantum behavior.
The reflection happening only on the front surface and the back surface is an approximation. There is reflection in the bulk of the glass (RF says it in the first chapter if I remember well, he also says that it is not the same photon entering as leaving the glass, it has been emitted and...