Can I apply for a deadline extension for my thesis defense? In which cases?
Yes. The prolongation is limited to exceptional circumstances, such as in cases of serious and long illness, for example. In most cases. The replacement of advisor in the middle of the program, work commitments made by the student, problems of working and studying simultaneously, and so forth are not considered exceptional circumstances.

Is it enough for me to defend the thesis to be eligible for the diploma?
No. You must obey the required standard deadlines; you must have achieved all the required credits; you must have a Transfer Evaluation Index (TEI) of 3.0 or higher; you must provide proof of proficiency in the English language; you must have published a scientific paper in a B2 or higher journal, according to the Qualis system of CAPES for the Management area; and, as a matter of course, you must have your thesis approved by the examination board.

Is the diploma issued automatically?
No. The certificate is granted according to a bureaucratic process established by the PRPPG. Besides the basic requirements for being eligible for the diploma, there is also a list of requirements (Check list) with a number of documents (some provided by PPG, some provided by the student) and other requirements of PRPPG for the issuing of the diploma.