Is this the best time to petition f2a if Visa bulletin is current?

It is best to consult an immigration attorney. Generally you need to be in the US for over 60 days on a B2 to have someone file for you . Bring...

IN HOW MANY DAYS NVC SEND A FILE TO US CONSULATE ABROAD? I MALED ALL DOCUMENTS TO NVC IN HOW MANY DAYS I GET INTERVIEW LETTER ?

It can take 6 months to a year.

Can uscis or NVC change my case from F2A to F2B ? knowing my priority date should be current right now

I agree with my colleagues.

Sb1 visa and citizenship

You should consult the attorney who helped you obtain the sb1 visa. I think it will be very difficult to convince USCIS that you are eligible...

Can I petition my parents to enter the US permanently as a permanent resident?

You must first become a US citizen before you can sponsor your parents. So the first step in the process will be for you apply for citizenship...

Does he need to file an separate petition for her 4 month daughter whose in India?

I agree with my colleagues. The child will be coming as the wife's dependant.

I agree with my colleagues. You need to be patient. Or you can request it right away and face abandoning your application.

I missed to answer questions part 3 - question 6 & 7 in I-90 e-filing form. Please let me know how to fix it? Thanks.

I agree with my colleagues. All you can do is wait for a RFE and be sure to respond it.

Behavior technician what visa is possible? Currently holding a J1.

You may get a H1. However you should consult an immigration attorney as you may be subject to a 2 year abroad requirement.

If the guy is on OPT can the spouse ( currently in US on academic H1) go on a dependent F2 visa?

Yes it is possible.