Is it permissible, from a Sharia perspective, to address the wife's mother as "Mama" to please her and to please the wife?

It is permissible to address the wife's mother as "Mama" or "Ya Ummi" (my mother) for three considerations: out of respect for her, to please her and the wife and to show affection to both of them, and because no legal prohibition results from it. She is permanently forbidden to the husband, unlike a man naming his wife by someone forbidden to him, like his sister or mother, as that bears a resemblance to Dhihar.