No. LG G6 does not support Tata DoCoMo CDMA. But it does support Tata DoCoMo GSM Sim cards.
LG G6 64GB comes in 2 different colors in India - Black and Titanium.
No. LG G6 does not have notifiation light.
Yes, our sources in LG has confirmed that Oreo update will release soon for LG G6.
(This answer was written on 27 March 2018).
The LG G6 is still a decent phone if you can find it cheap.