1) Is it permissible to replace the letter 'Jeem' with 'Sheen' in the saying: "Indeed, You are Praiseworthy, Glorious (Hamid Majeed)"? 2) Is it obligatory for the congregant (ma'mum) to combine prayers if the Imam does so?

Replacing the letter 'jim' with 'shin' in the word "Majeed" (مَجِيد) to become "Masheed" (مَشِيد) is a linguistic error (laḥn) that alters the meaning, as "Masheed" refers to something elevated. The phrase "Innaka Hamidun Majeed" (Indeed, You are Praiseworthy, Glorious) is part of the Abrahamic prayer (Salat al-Ibrahimiyyah), and it is among the recommended utterances in prayer. The prayer is not invalidated by such a linguistic error, especially if it is due to an accent or foreign tongue. However, the worshiper should strive to correct their pronunciation. As for combining prayers, the follower is not obligated to combine prayers if their Imam combines them. It is permissible for the follower to pray the first prayer with the Imam and then pray the second prayer at its designated time, either alone or with others.