Can I file I-765 (EAD Card) with my I-485 while I have just received an EAD through Student: Post Completion OPT?

There I no benefit to filing now, since adjustments take only 3 to 6 months, and you can file in 9 months if your case is still pending.

How long does it take for the USCIS to process a case after it was terminated from immigratin proceedings?

There is a wide range of how long it takes, you should not have needed to refile, when CIS incorrectly sent your case to storage. 6 months to a year.

Filing green-card from OPT by marrying citizen

You cannot do it. You can get a green card for marrying a person with intent to spend a life together, not marrying them to get a green card.

How I can know if my green card is safe and there is no error in the approval process

If you were already married for two years when granted adjustment you should not need to file to remove condition. In any case, if you are not a...

What evidence will i need to prove that I did not abandon my green card/ LPR status?

Submit the evidence you mentioned, your family ties to the U.S. and the fact that this was to go away for school.

Do I need to get my passport stamped for L2 to H1B COS?

Yes, you will need an H1b visa in your passport to be admitted to the U.S. as an H1b. Check the embassy website for how long it takes.

Is there any influence on reentry to US with a court date ahead? F1 visa

Not sure what Petit Legancy is, but if it is not a criminal charge, then there should be no issue.

Quite possibly, you need to research this, there may be private scholarships, or schools may offer them, there is no law on the subject.

I'm us ctn my husband was deported in 2005. Will this new immigration law help us faster. He was given 10 yrs to re-apply.

It does not appear that the new law will have any impact on this situation.

Why is the guyana embassy requesting a joint sponsor?

Perhaps there are a lot of dependents, and he is sponsoring 3 more dependents. Show an attorney the I-864 and supporting documents.