Yes, Nokia 1 does have the Google Assistant in-built.
Yes, Nokia 1 have the removable battery.
Yes, Nokia 1 does have the support for 18 Indian languages. You can change the system language from the English to Punjabi easily.
Yes, Nokia 1 does have Google Maps support. It runs on Android 8.1 Oreo Go edition.
The Nokia 1 is an inexpensive Android smartphone, and as you can tell from the Nokia 1 review, you very much get what you pay for.