Is it permissible for a non-mahram woman to uncover the face of a deceased man while he is in the morgue for the purpose of greeting and bidding farewell?

It is not permissible for a woman to unveil the face of a non-mahram man by touching it, unless there is a legitimate and recognized necessity. As for merely looking at his face without touching, there is no harm in it, despite there being no need for it. There has been a difference of opinion regarding the ruling on unveiling the face of the deceased, and the correct view is that it is permissible.