Some lawyers have no idea what they are talking about... We have seen many in VisaJourney. Just because lawyers say something it does not mean it is accurate.
Sorry, but you are starting over.
With immigration you really need to pause, count up to a 1000 and then proceed with action. Especially if it's a cancellation.
Mmmm... Not 100% true. Officers have discretion to ask about travel to other countries as a way to prove that the applicant is not just trying to establish themselves in another country.
What country are we talking about? That's important information that will give you a more accurate reply.
Is there an age difference?
Has the petitioner applied for a visa before?
This person has already filed their 751. And no, it does not always "stick". When I filed for N400, a year after my 751, USCIS sent me to my older State for biometrics.