Change of status Stamping from F1 to H1B in Canada

Generally that is permissible, but you should discuss it with your company's immigration counsel, as they are in a better place to know your file...

Can I-140 and I-485 forms be filed simultaneously?

Yes, if a green card is available in that category (which they are for EB-1s), the I-485 can be filed simultaneously with the I-140, or anytime...

Can I work for a US company during my vacation time abroad if I'm on H1b?

U.S. immigration law is only concerned with what you do within the borders of the U.S There is no immigration prohibition on your providing...

Duplicate copy Certificate of Naturalization

Your friend needs to file Form N-565, Application to Replace Naturalization Certificate. Information and instructions can be found at the USCIS...

Can a US citizen live and work in Australia and continue to remain a US citizen?

Yes, you can maintain your U.S. citizenship while being a permanent resident in another country. There may be tax implications to this, however,...

Can we port priority date if previous employer revoke my greeen card application?

Yes, even if your prior employer revokes the I-140, you can still retain that priority date on any subsequent I-140 petition.

Is it a problem if my passport expires during the green card process?

The expiration of your passport shouldn't impact your pending adjustment of status application - you should still renew your passport through the...

Yes, the petition can be withdrawn, but only the H-1B sponsor/petitioner can withdraw the petition.

B-2 (Visitor for tourism) to F-1 (Student), and then to i-485 (adjustment of Status)

According to your e-mail, your "Place of last entry" and status that you entered in, refer back to your last entry to the U.S. in B-2 status - not...

What is the prerequisite stay limit for L1B holders to apply for I-140 EB1-1A petition?

There is no minimum stay requirement to file an I-140 petition, in any category.