This is a Family class sponsorship section. Not a student section. BTW you committed misrepresentation by not disclosing the US Visa rejection, and you will likely not be able to overcome that!
1. What terrible advice! You have not right of appeal when you lodge inland. Also living apart I would file outland. Many people file outland while in Canada.
2. You don't need to waste $5000+ on a representative unless you have a complicated case!