AirIndia Flight US2India tkt status

(06thFeb)Booked a refundable flight ticket using Diners Rewards for my sister+2Kids
AirIndia Flight: Newyork2Mumabi2Hyderabad(28-May-20) return(01-Aug-20)
HDFC smartbuy+Cleartrip
Now they don’t want to travel for at least an year due to Covid as Kids are just 6 yrs old
Contacted several times Diners Concierge, they ask me to contact AirIndia/Cleartrip and request for full refund.
Not able to contact on phone either of these. CT has no email and AI does not reply to my email.
Not able to see even cancellation charges on Cleartrip – in fact trip itself is not visible on CT. Diners Concierge not able to tell too, their reply is that, agent is not responding due to Covid situation.

Q1. Can I reschedule this ticket for new passengers, like my parents/her in-laws may visit them?
Q2. Should I cancel the tkts from smartbuy or Cleartrip link rcvd in email.
Q3. CT says AI flight from Newyork2Hyderabad cancelled, does this mean full trip cancelled? earlier it used to be so.
Your advice pls

Email from CT:
We regret to inform you that Air India has cancelled your EWR-BOM flight AI- 144.Unfortunately the airline has not provided an alternative.So we request you to contact Cleartrip via www.cleartrip.com/s...rt to check if any other flight option might work for you to check if any other flight option might work for you.
Important Note:
• While cancelling your trip online, please select “Flight cancelled by airline” as the reason for cancellation so that the appropriate refund can be processed.
• Due to COVID-19 situation, airline policies are different. The refund will be processed as per airline discretion. For airline policies check link (https://www.cleartrip.com/coronahelp/?utm_sourc...)