Well, she had no problem releasing the Pah-Wraiths until they rejected her. My guess is, if the choice was between Dukat and the Pah-Wraiths and the "Alpha Quadrant in flames" or accepting Sisko as the emissary to the prophets, she would rather go with the latter; which is what she did.
I don't think Dumar thought of mentioning Dukat to Kira. Dumar's main concern was freeing Cardassia from the Dominion, and Dukat asking to look like a Bajorian seemed irrelevant. And yes, he was still loyal to his old friend.