I need to travel back to my country due to urgency, will my previous stay be affected for that?

I agree with my colleagues. Contact your DSO prior to leaving the US for assistance with the F1 visa processing at the US Embassy.

Should I request another notice or USCIS will send by itself?

I agree with my colleagues. Contact USCIS if within 2 to 4 weeks of expiration at the latest. Contact a US immigration attorney for assistance.

I agree with my colleagues. Contact the company's US immigration attorney for assistance.

Is Biometric every time necessary when I apply for renewal of L2 based EAD?

I agree with my colleagues. If USCIS wants the biometrics, they will schedule the appointment. Otherwise they let you know it is not required.

Is there a way I can use my H1B petition to re-apply for CAP exemption?

I agree with my colleagues. Contact the company's US immigration attorney for assistance.

Can my last day of work with my J1 employer be January 28? If not, are the 3 days bad for future applications...

I agree with my colleagues. You may start work on the H1B 1/26/16 or later. Contact the company's US immigration attorney for assistance.

Can I be a silent/investor partner in a company in the US?

You may be an investor. You may not receive any income for employment without an EAD. Contact a US immigration attorney for assistance.

If you have an EAD, the answer will generally be yes. If you do not have an EAD, there may be income issues. Contact a US immigration attorney...

How can I extended a tourism visa which is valid 6 months, if it is done online please provide the website and any advice.

I agree with my colleagues. Review the I539 instructions at www.uscis.gov. Contact a US immigration attorney for assistance.

Can I get an F1 visa at the US Embassy in India if I enroll for 1 year certification program instead of an MS?

I agree with my colleagues. Contact your DSO to determine eligibility for your US school, SEVIS, and USCIS.