Is it a condition for the Imam or Friday preacher to wear specific attire, such as a turban and abaya, or is it permissible for him to lead people in prayer in a regular suit?

It is recommended to adorn oneself for prayer and Friday prayer with good clothing and perfume. There is no specific dress code required for the Imam or preacher, nor is the turban obligatory for them, but it is recommended to cover the head. Their prayer is valid even if their heads are uncovered. Wearing an abaya is not required unless it is the custom of the people of the land. There is no harm in the Imam leading prayer in a jacket and trousers if they are not tight and do not define the 'awrah (private parts). If they are tight, praying in them is disliked, unless the jacket or shirt covers the 'awrah.