  I present the factorization(s) of the Wheeler-DeWitt equation for vacuum FRW
minisuperspace universes of arbitrary Hartle-Hawking factor ordering, including
the so-called strictly isospectral supersymmetric method. By the latter means,
one can introduce an infinite class of singular FRW minisuperspace
wavefunctions characterized by a Darboux parameter that mathematically speaking
is a Riccati integration constant, while physically determines the position of
these strictly isospectral singularities on the Misner time axis
