Yes, Micromax Bharat 1 does have the removable 1800 mAh battery.
Yes, Micromax Bharat 1 (2018) does have the front camera.
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.
Yes, you can browse Facebook easily with the help of pre-installed Opera browser of Micromax Bharat 1.
Yes, Micromax Bharat 1 (2018) V409 does have the pre-installed WhatsApp application.