H1 in India for stamping H4 in USA

I have approved 797 and in USA for 8 Years.
Can I go to India in March for Stamping (Dropbox)
Same time, Can spouse(h4) and kid(h4) can stay in USA? (They have approved 797)
If yes, How many weeks, I can visit India

Yes. However if your H1B is denied for some reason, H4 dependents will need to leave the US asap.

I dont think there is a official guidance by USCIS on this. You can consult your employer’s immigration lawyer.