I 864 for multiple families?

I don't understand your confusion. Are you saying that you filed I-864 forms for people that are NOT permanent residents? Read the instructions...

If you get a divorce you won't get a greencard. I strongly suggest you 2 go for marriage counseling.

About I-130 application by US citizen for my brother .

Depending on your nationality this process will take 10-22 years. Talk to an attorney via Skype to explore alternatives.

Re-schedule the fingerprints. Since you were supposed to mail the card with the I-90, make an Infopass appointment to get your passport stamped.

Will it be a problem if we refile i485 - marriage based, if out of status?

Are you a US citizen? If so, her having worked on an EAD could not have been the reason for the denial. What was the reason the 485 was denied?

Should I have an i-864 form or i-864EZ form for Adjustment of Status to Permanent Residence?

The EZ is acceptable. But, your spouse should bring UPDATED info: recent pay stubs, new employer letter, 2019 tax return transcript.

I 864 Joint Sponsor?

You don't need a joint sponsor. Your 2019 tax return transcript is all that is required. But, go ahead and include that from 2018.

What are my requirements for the fiancé visa for my boyfriend to come here?

Have the two of you met face-to-face in the same room? If not, you need to have a Skype consultation with an attorney ... you can's sponsor him...

Why didn't you file the 485 along with the I-130? Yes, your husband needs to file the 864 and both of you need to have a Skype consultation with...

Will my F4 visa be denied?

Actually, working 'illegally' is a crime. If you have proof that you have been outside of the US for more than 10 years, you should be OK.