No. Micromax Bharat 5 has a mono speaker.
We have not come across any user's complaint about it so far. Since the model is new, you can expect that such issues reported by users only after a certain usage or time.
Yes, Micromax Bharat 5 does have the OTG support.
Yes, Micromax Bharat 5 pro does have the google assistant.
Micromax Bharat 5 pro has ARM Mali T720 MP1 GPU which is a single core GPU and its frequency is 600 MHz.