If you are travelling by plane, it will be the airline who will require the PRTD. I believe you should be able to enter via a land border without a PRTD.
If the sponsor withdraws then the application is cancelled.
I don't get what you mean by "but what will happen if the applicant did not the sponsor" please clarify.
The fact that you did not know how a failed claim can affect your chances for visas to other countries as well indicates that you really need to speak to an immigration lawyer.
You can try asking. I do not think it will hurt. Show proof of why it is urgent that you visit your son in the US if you decide to ask.
Also, having status in Canada will not guarantee a US visa, I hope the visa officer from the US embassy made that clear.
you are posting in the refugee section. wanting to work in Canada and wanting your kids to go to school here does not make you a refugee. Try the economic section of the forum.
also read https://www.canada.ca/en/immigration-refugees-citizenship/services/immigrate-canada/express-entry.html
1. You can apply to extend your stay but when at the border do not look like you are moving to Canada.
2. IMO, yes, because you cannot live in Canada. If you cross the border daily then it will be obvious you are trying to live here when you do not have that right yet.
3. If staying in Canada...
if the only h&c reason you have is you WANT to reunite, then the officer was extremely fair. your brother, upon graduation and acquiring a pgwp has a good chance to acquire pr on his own so long as he continues to pursue that path.
how far along are you? I ask because if I am reading the website correctly, there will be a 3 month wait to be eligible for MSP after moving from another province? I am not from BC though so I really have no idea if this is correct...
You still need to have a valid permit for you to be eligible after 18 months. There is no guarantee you will have one by then.
I think you are overwhelming yourself. Your first problem is if you'll even be approved for a visitor's visa. Suggest you focus on that.