Can I extend my b1/b2 visa based on taking care of my niece?

If CIS finds out you are helping with child care they will terminate your status and visa. You need to consult a Board Certified Immigration...

What are my option if my H1 get approved ?

You should talk to your attorney. AVVO is for people who might need a attorney. You should file the change of status now. If your H-1 is approved...

Do I get to apply for a green card through my parents who are green card holders and are going through citizenship procedure?

If you are single it takes about 8 years.

Can you switch joint sponsors for a petition for immigration?

You can file sponsors and delete sponsors however you wish.

Immigration ?

10-12 years from when the I-130 was filed.

How long I-130 will be valid after approval? While i-485 did not approve?

You apparently are in removal proceedings and/or you need a waiver. Either way you need a Board Certified Immigration attorney immediately.

How to apply ssn for my wife and kids age 4 and 8 ?

Without an EAD they must wait for the green card.

Doesn't your immigration attorney know any of this? She must wait for 90 days after her last entry and then file for a change of status to H-4. ...

While Early Filing for Naturalization, do you have to meet 30 months Physical Presence requirement?

It is actually more than 30 months of physical presence. What you do now is apply again for naturalization.

Will i be out of status if i (f2) while my f1 is out of US with leave of absence?

If it is a medical leave of absence in the US then you both will maintain your status. However, if the F-1 leaves the US for anything other than a...