can someone from India who still have the bitcoin transfer to my Coinbase account in US?

At a purely Bitcoin protocol level, yes - Bitcoin does not differentiate between users, locations, individuals, companies, or any other thing. All Bitcoin transactions are equal.

Is there any transfer fees or exchange fees that we need to pay in either countries

You will incur the network fees for the Bitcoin transaction, which vary on the network state and transaction size.

and is it legal to transfer?

You should consult a lawyer in your jurisdiction.