This is my response to you:
1. The children can easily sell the property;
2. There are some rules, which you can find on this link: https://www.mea.gov.in/property-related-matters-of-nri-oci.htm
3. There might be some tax implications on the foreign nationals;
4. The buyer may not face extra tax implications, stamp duty and registration charges;
5. Rest, you can take assistance of a CA to understand the capital gains statement.