H4 query

[MMonteiro]

I am in India and I have a valid H1B approved petition from Company A in India. I also have a valid H1B visa for the duration mentioned in the H1B petition. I have never travelled to US with my H1B petition. My wife is having a valid H4 visa for the same duration applied based on my H1B approved petition. I have a new offer from Company B in US and they would like to transfer my H1B petition to their company and have me travel to US along with my family to join Company B. Below are my questions?
1. Can I travel to the US with my existing H1B visa (from Company A) after the new H1B petition is approved for Company B or do i need to apply for another visa from company B?
2. Do i need to file I-539 for my wife for change of my company? OR
3. Can she just travel to US with current H4 visa (from company A) using my new H1B petition (from Company B)?
4. Also, does my son who is newly born in India (he does not have an H4 status) also needs to file for I-539 or do i just apply for an H4 visa based on my H1B petition?

Any help on the above is appreciated.

Thanks

[shervin143]

1. Can I travel to the US with my existing H1B visa (from Company A) after the new H1B petition is approved for Company B or do i need to apply for another visa from company B?
>>> You can travel using the existing visa. You can also gofor a new visa, if you prefer to do that.

2. Do i need to file I-539 for my wife for change of my company? OR
>>> You cannot file I-539 for a person who is outside U.S.

3. Can she just travel to US with current H4 visa (from company A) using my new H1B petition (from Company B)?
>>> Yes.

4. Also, does my son who is newly born in India (he does not have an H4 status) also needs to file for I-539 or do i just apply for an H4 visa based on my H1B petition?
>>> You need to get the H4 visa for you son. I-539 cannot be filed for a person staying outside U.S. That is filed to extend the status of a dependent who is already inside U.S.