Is it permissible for a wife to kiss her deceased husband before burial as a farewell, and does he become unlawful for her after his death?

It is permissible for the wife, relatives, and friends to kiss the face of the deceased. Evidence for this is that the Prophet, peace and blessings be upon him, kissed Uthman ibn Mazun when he was deceased, and similarly, Abu Bakr did so with the Messenger of Allah, peace and blessings be upon him, after his passing. Permissibility is also indicated by the Prophet's saying to Aisha, that if she were to die before him, he would wash and shroud her. If washing and shrouding are permissible, which involve direct contact, then a farewell kiss is even more deserving of permissibility.