Update, you make sure you have a cheap outbound flight booked (e.g BKK to Siem Reap). Check in staff at departure still may want to see you will exit from the kingdom within 30 days. Of course you will not use it, but book it before you leave Canada.
You will apply for 60 days Single Entry Tourist Visa that you can extend when you are in Thailand, yielding a total of 90 days to stay. For the return flight, you just stay 1 week so you need no visa at all (30 days exemption)
not advisable unless you are looking for a travel insurance. If you need a plan for a long stay in the kingdom it's still better to have someone you can talk face to face. Or you can opt for the ultimate solution, marry an insurance agent 😀