There are generally two types of visas available to those wishing to work in Thailand. Non-immigrant B visas and non-immigrant O visas. For a non-B a Thai company will have to be involved in applying for the visa, this is not possible to do on your own (a few exceptions apply but not applicable here). This f does not grant you the right to work though, you still need a work permit that the company will also need to apply for on your behalf. For a non-O, you can do it on your own, but you must be married to a Thai and keep a large sum in a Thai bank account prior to applying. This also does not grant you a right to work, a Thai company will apply for a work permit on your behalf. So the sort answer is you can't do any of it on your own, a company will have to hire you before any of this is set in motion.

The only issue you'll face is that the 12th of May is a Saturday and immigration will be closed. Monday the 14th is a holiday too, so immigration will be closed. Your options are the 11th or the 15th.

If the school wants to hire her legally (work permit etc) she could go to school on the non-B.

It will be fine. The airlines only look at the photo identification page, and only to match the id to the reservation.

My visa expired a few years ago, I'm on extensions of stay. Don't worry about what that means if you don't know - basically if the airline looked at my "visa" it would be years old and they're have to go searching through other pages to find the current stamp that says I'm here legally. That's never happened at an airport for a domestic flight (I'm usually in the air a few times a month, most times I don't even bother with the passport). If they were looking for visas, I wouldn't be able to board.

It will not be an issue if you fly, the airlines are looking to make positive identification, they are not concerned about your legal status. I didn't know there have been issues of people being checked by immigration leaving Phuket, that's interesting news to me. Phuket is just a province/island, no special status.

Last time I was there was for work, in and out by plane same day and I didn't even take my passport (used Thai driver's license for ID).

The process is simple and straightforward, I just don't know about the stamps :(

You can get a bus from CM to the border pretty easily at the bus station in Chiang Mai. They drop you off pretty close to the border, it's been so long though that I forget if you can walk it need to get another form of transportation to the border. If you do it's only a few minutes from the bus station. On the Thai side they'll stamp you out of Thailand, and once in Myanmar they'll do whatever they do. When you cross into Myanmar they'll keep your passport at the border and you can either go into Tacheliek and have a washer around the market or just go straight back to Thailand. Thailand will give you another stamp (if you are eligible*) for 30 days visa exempt and you're done! Back in Thailand with a 30 day reprieve. For this there's no need to visit embassies out do anything beforehand. Show up at the border, leave Thailand (even if only for the time it takes to get stamped in and out of Myanmar) and come back with 30 more days.

I've heard and read about buses from Chiang Mai to the border that aren't from the bus station? Maybe "green bus" or something like that. Do some googling and see if that's what you're looking for.

Wish I had definite answers for all of your questions.

If you're OK with just 30 days you can definitely do it, if you NEED the 60 day tourist visa I don't see any ways to get that without a risk of running out of room.

Anyone know what happens if that does occur?

Malaysia and Singapore are both options for a border bounce with very little space used. Neither is bussable from CM. Maybe someone with recent experience at Mae Sai will chime in with the Myanmar stamp situation?

I'm not sure what goes in your passport for those border crossings, I haven't done one in years. But my experience asking immigration officers to conserve space and put stamps where I want them ended at a South African immigration checkpoint when the office sternly told me he'd put the stamp where he pleases. It's just not something I'm pushy about and don't think that's a good way to engage. If you can get it and back on just stamps on a single page that's probably your best bet. Get your 30 days and then apply for a new book from your embassy

Hmmm good question. I'm no expert, but that last free page will have a Thai exit stamp and entrance stamp into whichever country you're getting a visa in, then aside from the visa you'll need space for an entry stamp back into Thailand. Sounds like you need a new passport ASAP and you're screwed until then. But someone may have a solution for you that I'm unaware of

That last part, about domestic travel, needs a caveat: needs to be a Thai issued ID. So a driver's license or pink ID card would work but not a school ID or foreign driver's license