H1 Ext Approved, H4 pending Approval

[nj29]

Hi,

My H1 Extension was approved on 16th Feb, 2018 but H4 of my dependents (wife and daughter) is still not approved. We are planning to travel to India on a vacation.

2 questions - 

1) Can my dependents go for visa stamping based on my H1 i797?
2) Will traveling out of US, before H4 extension approval, affect my dependent's i539 processing in anyway?

Any help would be appreciated. thanks.