Will there be any problem if I apply for student or spouse visa in future?

There may be problems. Much more information is necessary.

Can I file two H1B petitions from different employers at the same time? Do they have to be filed under premium process(BOTH)?

Any employer can file an H-1B petition on your behalf, potentially.

How long does Certification from DOL take to issue on EB

t generally takes about 7 months for a PERM labor certification application. Note that PERM does not extend or change one's immigration status.

This should not be considered unauthoirzed "employment."

Who can fill out the petition for alien entreprenuer Form I 526?

It would be recommended that this person hire an experienced immigration attorney to assist with any EB-5 matters.

Bring your State-issued ID as well for the biometrics appointment. You can explain the lost I-551 at the naturalization interview.

Can I apply to H1B to H4 COS now and H4 EAD along with spouse new H1B

You should take this list of questions to an attorney at a scheduled initial consultation.

What's the chance to get TN at a POE? My EAD application will become null right away in the meantime?

TN visas are generally issued at the POE. COnsult with an attorney to determine if the position and your qualifications meet the TN criteria.

I'm currently working under my OPT (optional practical training, will getting married effect my ability to work?

Yes, you would still be bale to work under your OPT and then with a new EAD issued once you have filed for adjustment of status. Consult with a...

Is it possible to convert H4 to J1 from canada? I am an Indian citizen.

No, you would have to obtain a new visa from your home country.