Etymologically, angel just means "messenger". In the bible it was used not only for supernatural "angels of God", but of human prophets, and even ordinary secular couriers.
Interestingly enough, some consider the Seraphim, whose name means "the burning ones", to be quasi-reptilian, the "burning" in this case being the "burning sensation" of their venom.
So really I don't think calling Jills Angels is really all that far off.