The DS260 is signed by applicant not by petitioner.

Yes rescheduling often happens and this is normal.

Yes you can change status to B1 while in the US.

No this estimate is often not accurate.

An attorney must review the final disposition to understand the possible consequences.

You will need a cosignor if your son’s income is not sufficient.

Yes this is normal for processing of your case to continue.

No this shouldn’t be an issue and you can bring the disposition at time of oath ceremony.

I agree with my colleague regarding lawsuits against the government of this nature. Consult with an attorney for guidance re: case.

USC spouse or employer is the fastest way to obtain GC.