There are several issues in the scenario you are asking about. Your employer's immigration attorney is in the best position to advise you as the...

L1 to L2 coversion

Once your status is changed from L-1 to L-2 you are not longer eligible to be employed without the EAD. You can check processing times on the USCIS...

She is permitted to request the B-2. There is likely a better probability of being grant a J-2.

Can i submit a new financial affidavit?

Wait until and if USCIS asks for another.

Should I go for I-140 premium processing?

If you want a decision sooner than regular processing use premium processing. The rest has no basis.

Can I apply for Citizenship under the 4 years 1 day rule?

Possibly if there has been no travel outside the US since and you maintained residence for the 5 years and meet the other resident requirements....

Can I file my Green card in EB2 category

It is possible if the position requires an advanced degree and you meet the requirements for the position and your employer is willing to file a...

If i change my status from Tourist Visa to Studant Visa, can i leave the U.S.A and come back?

if you depart while it is pending you will be considered to have abandoned your application and it should be denied. If you leave after approval...

Can I go back to home country while adjustment of status is filed for me?

Speak with your immigration attorney about advance parole before departing the US.

What Can I Do?

You can continue contacting USCIS and wait, seek legal assistance and consider a mandamus action, contact your congress person or senator.