I would look into AOPA. If you get their premium membership it includes consultation on Medical concerns which includes a lawyer. They will likely take the time to answer many of your questions.
I think an AME and HR / Recruiters can see past 10yr old mistakes given your current responsibilities and attitude. But it will be uphill, and depend on IF its a disqualifying offense where HR hands are tied.
2 years ago I did a survey of Regional Airlines about how they handle DUIs. On avg it required a clean record for 5yr and proof of entry to Canada.
Most Majors seemed to allow 1 DUI from distant past.
Expect these to get stricter now that pilots are expendable. Already see airlines and Corporate adjusting their hiring standards to this “new normal”.
Canada will likely be your biggest hurdle. A Temporary Residency Permit allows entry but has a high bar to receive. 5yrs after all court sentences are completed you can apply for Permanent Rehabilitation Status. Either of these would require assistance from a specialized Attorney and approx $1500-$3000 each time. This cost does not guarantee anything, only that they will review your request.
There are other opportunities for pilots besides airlines. I have 2 friends making 100k flying medical supplies in PC12s at night. 5day/wk overnight job, home almost every day, weekends off. So there are options with a good network of friends and interview skills.
Given your age of Approx 30, do a spread sheet on your net worth at age 65. One column for keep doing what youre doing, and another for transitioning to pilot. (Loss of income from time commitment, Cost of training, CFI wage, Regional FO wage, Regional Capt wage, ect) Expect 2yr training, 2yr CFI, 2-5yr Regional FO, Regional Capt, etc.
Its a huge decision with a lot of moving parts. Act like your favorite dispatcher and take the time to plan it out as accurately as you can.
GL,
Chris