Canada may require a transit visa depending on nationality. As I understand, your visa will be a sticker in your passport, taking up the entire page. This visa may have your dates of travel printed on it. There is no stamp as far as I know. I don't know about extensions with American tourist visas, because visas are supposed to be issued by your home country usa embassy. I was led to believe that if you wanted to extend, you had to travel back to (if you're thai) us embassy bangkok and then return to USA again.
I've sent several ups/dhl to Thailand. I've found that whatever you paid for an item, triple it's cost to determine shipping and customs fees
Note, if anything is quarantined, (example, food like tea leaves) it will be held in customs for as long as they bloody well like, AND in addition to fees, and an import license (IF they approve) they will charge you a daily rate for storage.
If you want to relax, you can hire an agent to represent you. If you're going to be in CNX, may I recommend the chiang mai visa shop? I mean, he's an agent, who will charge a fee. And you will need to be present as thai immigration always takes photos. But he could tell you everything you need. And he could help you maybe bypass a few steps to be done in one hour. For the peace of mind, it's probably worth a little extra dollars
delta initially denied me boarding because my trip was 31 days. This seems to happen frequently. I booked a 120 dollar throw away ticket to Cambodia. Delta wasn't even interested in it. They just called their supervisors and put on some sort of override.
My question is, yes, your friend can get in, AND pay for an extension if needed. But if there is already an approval in the works, does it absolutely have to be issued bunches LA consulate?