In my opinion,
1. A Company Secretary appointed on 02/01/2016 can sign Form MGT-7 as a Company Secretary in employment of the company is to sign MGT-7 as per Section 92 of the Companies Act, 2013. However it would be better if he is also so authorised by a Board Resolution.
2. Yes, the Secretarial Auditor can sign the MGT-7 or on his willingness any PCS can sign the MGT-7 provided he is so authorised by a Board resolution.
3. PCS should be authorised by a Baord resolution to sign MGT-7.
Regards,
Anurag Sharma
M: 9831581824