Transfer of Shares of Pvt Ltd co

Father has 2 sons and 1 daughter. Father having shares of pvt Ltd company. Wants to transfer it to the 2 sons equally.

1. What Is the best way ? Gift , Will or Nomination ?
2. In case of gift , whether need to make registered gift deed ? What is the stamp duty charges and registration fees ? Can daughter challenge such nomination ?
3. In case of nomination, what are the procedures under the Companies Act relating to informing Roc and approving in any meeting ?
4. In case of will , can the daughter challenge the will ? What is the cost of will ? I have heard will is required to be registered and lawyer to get probate from court which costs around 90K.

Father has only 1 share certificate. So how will company transfer 50% each to the sons as there is no such method of parting away some shares behind the certificate in the columns and rows provided.

Please provide best solution taking into account better way out , no capital gains on transfer ie effective tax planning , no legal issues and minimum expenses.

What other consequences should assessee be careful about ?