1) I am Canadian, currently have TN visa, but unemployeed as this moment. For the Q22, does my hu*****and need to answer "Yes" for " Complete the information below if your relative is in the United States and will apply for adjustment of status"?
-Say "Yes".
What else do we need in order for me to have a job legally before I recieve the green card?
-Apply for the EAD by filing I-765 together with your I-485 filing.
If Yes, does the USCIS location matters? in the other word, does it matter if we choose Detroit, or Chicago? for "Your relative is in the United States and will apply for adjustment of status to that of a lawful permanent resident at the USCIS office in"?
-Choose the USCIS local office in your living area.
See:
https://egov.uscis.gov/crisgwi/go?action=offices.type&OfficeLocator.office_type=LO#FormTop
Questions re I485
Part2, I currently have TN visa, my hu*****and is US citizen and file I130 for me, should I check box A even though we will file I130 and I485 together?
-Correct.
Part3 Section A, I had B1/B2 visa with my Chinese passport, valid till 2014, now I am canadian, should I still fill in the non immigration visa section or state as N/A?
-Say "No visa issued/Canadian" in the "Nonimmigrant Visa Number" part and leave the other related parts blank.