1.) I think you definitely have a chance for Mac if you kill the CASPer (plus you have a Masters degree, so that gives you +1%). Perhaps UofT with their wGPA system, bringing your GPA up higher as well.
2.) You would have to be super interested in the particular undergrad program.
3.) Since you graduated from your undergrad already, I think some schools would be able to count the extra courses done outside of your degree as within your cGPA, whereas some schools actually won't.
4.) Depends on the reason - for example, if it's to boost GPA, check if the schools acknowledge thos