No. Micromax Bharat 1 V409 does not have Google Play store in the phone.
Yes, Micromax Bharat 1 (2018) V409 does have the pre-installed WhatsApp application.
No. Micromax Bharat 1 (2018) V409 does not have the OTG support.
Yes, Micromax V409 (Bharat 1 2018) does have the support for the Marathi language. You can change the entire phone's language to the Marathi. You can store contacts, write messages in Marathi, too.