Do a Freedom of Information Act Request for your mother's Alien file of the National Records Center. Good luck.

Am I qualified to make this sponsorship? What other documents I need to submit on top of form i-134 and bank account?

You can provide an invitation letter and include that you will put him on the return plane home. The most important thing is that he has...

Since my h1 extension is due in Oct'16 and i am joint sponsor, will this affect/cause RFE for oour AOS appplication

As previously explained, you may use your income but would need to show that this income will continue.

My friend got hit by a gang member (they are high school students)

Check out the U visa for your friend: ...

Do I need to travel out of US to get the renewal H1-B stamped?

IF you travel outside the U.S., then you will need H-1B visa stamping. IF you do not travel outside the U.S., then you will not need it.

This is a perfect example why individuals need to consult with an immigration attorney before they do anything. Whoever was helping you (sounds...

Do I need to worry since I submitted the DS 260 after the expiration date?

You should be fine. The most important thing with NVC is that you stay in communication with them within one year.

Am I inadmissible? Will I be able to apply for AoS after marriage to a USC (bonafide marriage)?

You should put all of the relevant documents in a folder and consult with an experienced immigration attorney. I don't know why the NTA was issued...

Can I go to Europe (Ireland) If I am a LPR?

Your passport and green card is what you need to travel outside the U.S.

Does the affidavits as a proof for our "bona fide" marriage should be notarized?

Yes, affidavits should be notarized. Declarations are under penalty of perjury and not notarized.