Change of status from H1 to H4, if H1 visa is not approved

[krishna_murthy1]

My wife and I are currently in US working on separate H1s. For both of us I140 is also approved.
My 2 kids are on H4 as dependants of my H1.

It has been quite sometime we had gone to India, and we are planning to go this summer.
As H1 stamping is always attached with risk, we would like to plan in a safer manner.

I, along with my kids are planning to travel to India first and attend visa interview and if everything goes well 
my wife travels to India later and will attend visa interview.

In worst sistuation Kids and my stamping doesn't go well what would be my options, request your response to my questions

1) Can Kids and I attend for H4 stamping
2) If yes to H4 stamping, Can we attend immediately. What can be the suggestible gap between H1 and H4 stamping, if H1 is not approved?
3) Suppose if H4 stamping goes well, after we come back to US can I change my status from H4 to H1 
For Information, my petition is still valid till 2020 and both of our H1 extensions are over 6 yr period.
4) what happens to my I140 as I change from H1 to H4 status. 

 

Thanks & Regards,

Krishna

[Tjgarla]

YEs to everything 

[krishna_murthy1]

Thanks for the response.  I couldn't get as what happens to my I140, would it become invalid?

Appreciate your response.