As said the two you need are a Residence Certificate from Phuket Immigration Office (300 baht) and a medical certificate from a health clinic (100-200 baht). Copies of passport, photo page, visa or extension. You will most likely be given an appointment time to return the first time you visit the Land Transport Office, but possible you could be served that day and therefore you should have these two required items with you when you go the first time.
If you have a valid foreign driver's license (with International Driving *Permit* or in English) you can avoid the theory and practical driving tests at the Land Transport Office. No particular benefit to using a driving school in this case.
In Phuket you get the Certificate of Residence from Phuket Town immigration office while you wait. They ask for 300 baht. If you decline to pay you will likely still get the certificate (I think it's worth 300, so I pay). You need one for each type of license, car and motorcycle. In Phuket, you can get photos done at a little shop behind the immigration office.
Yes, 300 baht asked for the Certificate of Residence in Phuket. The Phuket Land Transport Office doesn't accept the yellow house registration book as proof of address.
Yes, you would first go to Phuket Immigration to obtain a Certificate of Residence (they will ask for 300 baht). Then, less than a kilometer away is the Land Transport Office where you can get your driver's license.
Although they can insist that you have an International Driver's Permit, often they will accept a valid foreign license if it's in English, so Canadian should be fine without translation required.