yes it is possible

Nothing prevents them from marrying.

yes

Indian marriages under Buddhism are governed by the Hindu Marriage Act, 1955,which provides for the conditions of a marriage where under the bridegroom should be the age of 21 years and bride of 18 years, they both should not be within the degree of prohibited relationship.

There is no legal barrier to them marrying as their marriage does not come within the prohibited degrees of relationship.

thanks for your appreciation

Thank you for appreciation.