Cheque bouncing

A. Can a person be convicted under S. 138 NI Act due to a mismatch of signature?

  

     Yes. 3 cases to substantiate the same

1. Laxmi Dyechem v. State of Gujarat  (2012) 13 SCC [para. 16, para. 16.1, para. 16.2, para. 30, para. 31]  
2. Om Prakash Singh v. State of UP (2015) 89 ACC 497 [para. 12-16] 
3. Sushil Kr. Mondal v. Probodh Dihingia (2015) 5 GLR 825 [Page 827 relevant]

B. Can a person be convicted under S. 138 NI Act if cheque bounces due to "account closed"?

Yes, he can be. "Account closed" would amount to returning the cheque unpaid because the amount of money standing to the credit of that account is insufficient to honour the cheque as envisaged u/S. 138 of the Act. 

(As held in the case of NEPC Micon Ltd. v. Magma Leasing Ltd. [Pages 253, 254 relevant])