Both spouse and child need their own I-130s.

Having HIV does not make someone inadmissible. Therefore, even if the officer did know, it would be irrelevant.

"U.S. consular officers overseas will deny any B visa application from an applicant whom the consular officer has reason to believe is traveling...

You cannot become a US Citizen without having an approved I-751. That is the first step. Best to privately consult with an attorney.

You may keep the appointment and then submit the N-600. The order is irrelevant. Make sure to keep a file with a copy of your Naturalization...

You need to honestly report your travel history or face denial or denaturalization. Therefore, yes, the officer will have your travel history.

Check your passport, emails, etc. If you crossed, into Canada by vehicle, you may obtain your Travel History Report....

Unfortunately, sibling visas take between 15 and 20 years.

Yes that sound acceptable. However, you should have a lawyer and be following that lawyer's guidance.

If the drive way is shared, both of you must share.