Does ASC (USCIS Application Support Center) Florida start to send biometrics notices for I-485 since they open on July 20th? ?

Yes as ASCs are reopening, you should expect your biometrics to be scheduled shortly.

Help!! Its been 77 days since my case got approved and sent to NVC?

You may consider work with an attorney to contact NVC.

File I-130 sister petition?

Unsure which category your aunt filed under as there is no category for nieces/nephews. Please provide more information through consult.

Should my I-864 sponsor need to be the guarantor, if needed, in case of renting a new apartment?

No the cosignor does not need to be the same person.

Doe F2 have to leave USA after marriage to the USA citizen

You will lose the dependent visa status if spouse’s status is lost. And yes you may reapply through second marriage but must be a good faith...

I was granted assyum on the 03/19/17 so when do I apply for naturalization?

Four years after you were granted permanent residency.

Yes you may however the I485 would be adjudicated in court after I360. Best to consult with an attorney in private to review a case.

You may submit a withdrawal letter to the service center that is processing your case.

I-751 notice of intent do deny based on prior sham marriage

A review of the NOID must be done before guidance can be provided about merits of case. Best to speak with an attorney in private.

No this should not be an issue and can be disclosed at start of interview.