It is well-known that several regularization methods can work equally well for the removal of ultraviolet divergences in the
stress-energy tensor of quantum fields in curved spacetime. Their mutual relations are known, and discrepancies explained.
This formal structure of regularization schemes for quantum fields in curved spacetime should remain intact when
applied to the regularization of the noise kernel in general curved spacetimes; it is the meaning and relevance of
regularization of the noise kernel which is more of a concern (see comments below). Specific considerations will of
course enter for each method. But for the methods employed so far, such as zeta-function, point separation,
dimensional, smeared-field, applied to simple cases (Casimir, Einstein, thermal fields) there is no new inconsistency or
discrepancy.