The 10 year bar is automatic upon exit after 1+ year of overstay. If you had left 9 days earlier, it would have only been a 3 year bar.
You can apply for a tourist visa, but until the 10 years is up you are barred. The CO can request a waiver for you, but it's extremely unlikely to happen.
After the 10years, you are no longer barred, but it's still not likely to happen given your circumstances (US parents, US fiance/wife by then, etc., history of overstay, etc.).
Did you just not mention the violation or did you lie about it in response to a question (in documents or in conversation)? The former has no direct consequences. The latter is misrepresentation. If deemed material, that's a permanent bar.
You cannot submit a waiver for a tourist visa. The CO recommends you for one if they see fit. A lawyer will not help.
Yes, your parents can file for you. You would fall into F2B preference so long as you are and remain unmarried. ETA: ~7-10 years, assuming no changes to immigration.
A USC sibling can petition for you as well, but that wait is like ~15 years or so.
If you become engaged, she can file an I-129F (K-1 visa path) for you. Or you can marry (anywhere) and do an I-130 (CR-1/IR-1 visa path). After the interview, if you would otherwise be approved for the visa, you will be refused due to the 10 year bar. At that point, she can file an I-601 waiver on your behalf. It's ~$1000 and will add roughly 6-12 months to the timeline I believe. Just note you can't file until you are refused the K-1/CR-1 visa.
Note that she can only sponsor you for permanent residency...she can't help you visit or with other visas. This means you must be ready to 1) marry and 2) live within the US as a permanent resident. If your goal is just to visit your parents, then this is not the path for you.
Timelines
K-1: ~8-10 months from filing to interview, then ~6-12 months for the waiver.
CR-1/IR-1: ~12-14 months from filing to interview, then ~6-12 months for the waiver.
If your 10 year bar expires before the interview or before it's worth applying for the waiver, then no waiver is necessary.
This assumes you did not make a material misrepresentation (#2 above). If so, the I-601 waiver would also need to waive this.
An I-601 is a hardship waiver. Coming from Canada, it may be difficult to show a sufficient hardship, assuming she has the ability to move to Canada instead. Many Canadians are issued an I-601, so don't let that scare you, but you may want to consult a good immigration attorney for this path.
