Can you continue to stay in the US on a pending B2 tourist visa application after being terminated on H1B visa?

(1) Yes, you can. (2) How hard? -- it all depends if you qualify for the H1B position and that position is a speciality profession requiring at...

Can I change my status from B2 to H1B visa without leaving the US or will I have to travel to my home country to get visa stamp?

You do not have to leave the country just to get the visa stamp. You just need the Approved Notice for your Change of Status.

My F1 EAD to H4 petition is pending. Can i work until my h4 is approved or should stop by the start date given in i539 document?

Yes, you can work while awaiting the H4 EAD.

How can I prove a huge change of circumstances to reapply F1 visa for 3rd time ?!!

Changing states and/or changing majors are not the reasons for your denial. There are clearly issues in your case. As my colleague has correctly...

H1 approved with out i94.without exist the country can we update request to update

It's difficult to give you definitive answers without knowing more about your case. There is not enough information to be able to evaluate...

Converting the H1B premium will also speed up the H4.

When will I receive the interview letter after having my fingerprints done ?

If it is for a marriage based adjustment application, usually within about 60 - 90 days after.

No, not completing the program would not affect an unrelated green card application down the road.

Is the process still valid?!

A sibling alien relative petition can take many years to become current. Check the Dept of State's visa bulletin for current processing times.

Is it possible to change our immigrant interview from nairobi to the states as we are in the states apparently

You appear to be talking about two different processes for green card -- consular and adjustment of status. Retain a lawyer to assist you with the...