Is it considered hypocrisy for a female preacher to say something different when she is alone compared to what she says when she is with the Jama'at al-Da'wa wa al-Tabligh group, even if she confines herself to correct statements, for fear of reproach and losing the group's trust?

It is not hypocrisy for you to speak whatever beneficial words you wish, because adherence to what has not been enjoined by the Shari'ah is not necessary. Good company is one of the means that aid steadfastness, as in the Hadith: "A person is upon the religion of his intimate friend, so let one of you look at whom he befriends." It was not known of the Companions that they used to repeat specific phrases; rather, they used to study the Qur'an and Sunnah. The former and current leaders of the Tablighi Jamaat have denounced the formulation of short sentences to be memorized by their companions, emphasizing that what should be memorized by people are only the Qur'an and Hadith.