H1B-H4 stamping

Hello Everyone - I just received an email to submit my passport for H1B stamping. I am the principle applicant and my wife is a dependant. The problem is that my wife is out of India for a coursework and will return on Aug 31st. My question - Can I submit my passport now for H1B stamping and can she submit hers later for H4 stamping once she is back? Also, her passport expires in April 2018 and I797 approval notice is till May 2019. So can we get her stamping on the current passport and then renew her passport? Please let me know. Any advice is appreciated. Thank you.