Limit for registration

Interest or Discount covered under section 11 so interest on fd is exempt supply and included in limit of turnover

Aggregate turnover" means the aggregate value of all taxable supplies [excluding the value of inward supplies on which tax is payable by a person on reverse charge basis], exempt supplies, exports of goods or services or both and inter-State supplies of persons having the same Permanent Account Number, to be computed on all India basis but excludes central tax, State tax, Union territory tax, integrated tax and cess;

As Fixed deposit interest and interest on Loan is considered as exempt supply, it's required be added for calculation of threshold limit of 20/40/10 lakhs, as the case may be for GST registration.

Not be included for computing turnover in order to determine eligibility for Composition Scheme. (Refer order 1/2019 CT)

Yes for Registration must be included.