h4 visa stamping for my spouse and kids

Hii,

My wife and my two kids are planning to go India in this July and coming back just before one day of expiration of old visa…I m not going with them. I have valid extension till 2020.

My questions are:

  1. Should they go for visa stamping?

  2. If yes then its advisable to take drop box procedure?

  3. Is there any prob for getting stamp on their passport without me?

Plz reply as soon as possible

Thanks in advance…

Regards,

Mehta