yes true. I have lived in the Chiang Mai area for 10 years. March and April are the worst. For the rest of the year the air quality is much better than Bangkok
After the documents were submitted I was in the Netherlands at the time so I applied for an electronic visa. I did not want to go to the office in Bangkok
I can answer based on real experience. Prior to getting my long term visa I entered 8 or 9 times in one year. I left each time for work for 7-10 days and never needed and extension.
I am Dutch and needed to have my taxes officially translated. The translation company can stamp the documents then no notary required. Most do this automatically. The two texts need to be side by side. Go to a professional company in your home country.