Trading Account Balance Nominee

Have the following queries:-

  1. How to appoint a nominee for an existing Trading Account with Zerodha?
  2. Is it possible to convert an existingTrading Account in Individual Name to Joint Account - how to add Second Name?
  3. If Trading Account is in Joint names, should Demat Account also be Joint names - how to add Second Name?
  4. If nominee is appointed for Demat A/c. and such name is reflected in NSDL Statement, what is procedure for legal heir to get the shares transferred from IL&FS to the Demat A/c. held by legal heir in ICICI Direct?