I am separated with my husband (US Citizen) after we have jointly filled I751, what shall I do now?

I agree with my colleague - either reconcile or finalize the divorce by the time of interview & request a waiver of the joint filing requirement.

My mom filed for my sister immigration status but past away in the process how can I check on her status or where her case stand

Your sister may be able to continue the process through humanitarian reinstatement but will require review of case for further analysis.

Filed I-751 in feb. 2019. I havent recieved a biometrics apointment. Should I be worried?

You should contact USCIS directly to inquire about biometric appointment and any missed notices.

Should I file only one I 864 for my USC spouse who sponsoring me? together me made $30000 last year?

Your wife would file for the I864 and will require a co-signer given information provided. Consult with an attorney for further guidance.

Does my fiance qualify for k1 visa?

Yes he would qualify assuming you can establish your good faith relationship and having met in the last 2 years. Consult with an attorney prior to...

Household size on I 864?

If your son is a dependent then household size would be 3 including you and your spouse.

You can have the reentry permit sent to an overseas address if outside the US at time of issuance, however you must be in the US to apply and...

What happens if I go to my immigration master hearing with a police warrant?

The governments attorney will conduct a criminal background check and learn of this warrant. It is best to consult with an attorney right away...

Yes you may mention this incident at time of interview and it should not be an issue.

How old can I give a green card to my wife ?

You may apply assuming that your marriage is in good faith. Consult with an attorney for further guidance.