Is it authorized to issue a fatwa without prior notice to the author and without knowing the facts?

Assalarmualaikum wrahmatullahi wabarakatuhu, Hazarat Mufti Sahib, damat barakatuhu, An author, well known religious fagiour, secretary of a well known islamic organization in Myanmar was writing a biography of Prophet Muhammed(s) in a serise. He made unintensionally some mistakes which caused degraded the Prophet. The author did not know this factor but well known two religious college principals along with 70 of their college teachers without prior intimation to the author issued fatwa that the the author become kafir and bekilled. This fatwa were spreaded all over the city by their followers and it has been uneasy for the author to move around the city and felt sick. The mistake according to these two principals was that the author used ” he” in place of the Prophet, usage of proper noun. It was mentioned that The prophet and daughter of Abutalib Ummi Hani loved each other and the prophet implored Abu Talib for their marrage, usage of love matter and imploration. As soon as The author knew the matter he wrote to them for forgiveness and made known to them that he had already confessed to allah his guilty and said istigfar, tauba, kalma ect,. In fact these two principals and the author are all ahli Sunnat wal Jamaat and all are well known religious fagours, they should be united and well organized. If the author was made known by any means he was ready to correct the mistakes without any hesitation. In this points, the author would like to humbly ask the fatwa on the following points. (1) Without prior internal notice to the author and without knowing the real fact of the subject, Is it authorized issuance of that kind of fatwa? (2) Since They did so , according to Islam how those involved in this case should be named? (3) in view of above fact, Has the author became kafir or should he be killed? (4) To settle the matter peacefully what steps should be taken everybody? With many thanks and Salams.