H4 Visa for my wife and 10 months old kid

I got my H1b visa stamped but i’m still india and will be travellin this month.

I’m applying H4 for my wife and 10 months old kid.

can we submit my kids passport also on the same day as my wife interview or it has to be applied seperatley.

I’m going to a different location from my initial location in the petetion, will this cause any problem for my wife’s H4.

If we have apply my kids visa seperatley, do we have wait until my wife’s visa is stamped or can we apply with my visa alone.

Dear please read answer on this Process for H4 visa application for Wife and Child - L1, L2 Visa - RedBus2US Community

I am having same kind of case.