If you are an AOPA member, (and you should be, free 6 month membership for student pilots), give a call to their medical division and ask the questions. They have a very good set of of folks there that are familiar with haunted histories and how to overcome them. Get AOPA's legal plan, another tiny amount, and get in contact with a lawyer and ask the lawyer if expunging would be the best course of action. These are things to do BEFORE you let the FAA know about your past and desire to become a pilot. Also, get in contact with an AME (aviation medical examiner), jetcareers.com has one, who can tell you what would be needed with each item on your "been a bad boy" list and how things might be different if they were expunged. If you do have a series of events to disclose (and the aviation lawyer will say on the expunged ones), get in contact with Virtual Flight Surgeons (VFS), and have them walk you through the process of applying for a medical and being able to clear Canada's requirements. You may have to go through HIMS (a substance abuse recovery program), even if the problems were in the distant past. It may also be in your best interest to wait another few years, saving up even more, then starting. VFS will take out what could be multiple rounds of back and forth and make it just one set. They'll also be able to tell if you do have a chance.
You already have two strikes against you, why start out with three? Do your research WITHOUT contacting the FAA and giving them your name, rank, serial number, and so on. Learn now that the FAA is NOT your friend and there are many inspectors who would like nothing more than to keep punishing you for events in the past. While there are a few good FAA guys out there, many many more are not. Read the story of Bob Hoover's medical certificate if you need more justification to keep from contacting an Inspector.
Don't even bother to think about failing to disclose information when you do apply for a medical. That will end your career and probably put you in the federal pen for awhile.
It may be that the Sport Pilot certificate is the way to fly, and becoming a Sport Pilot Instructor is a way to make some money doing it (don't expect to live off of Sport Pilot Instructor income though).
Good luck!