I don't remember if it was ever suggested that Dr. Mora was a collaborator, in the sense that he helped the Cardassians develop weapons or engaged in any sinister experiments to be used against his own people, the Bajorans. So was Dr. Mora some kind of evil collaborator? I don't think so.
I can't recall Kira's opinion of Mora, if she indeed expressed any.
Some might consider Odo a collaborator. He was DS9's constable at one point during the occupation. However, according to Kira, Odo wasn't considered a collaborator. She said Odo was "the one man who stood apart from everyone else, the one who stood for justice." That was before she discovered that Odo did, at least once, helped the Cardassians execute innocent Bajorans.
About the occupation and about collaboration, Kira made this observation: "I guess the truth is that anyone who lived through the occupation had to get a little dirty." (Things Past)
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I thought the story about the relationship between Odo and Dr. Mora was very compelling. It was a moving scene when Odo and Mora reconciled. Their relationship might have started out badly, but it developed into a father-son relationship.
In "The Begotten", as Odo was mentoring the changeling infant, I think he came to understand what Dr. Mora must have experienced when Mora was trying to "raise" Odo. It might be a case of a person coming to appreciate one's parent more after that person becomes a parent.
Odo came to terms with the resentment he held against Mora for all those experiments Mora put Odo through. It was a very good episode.