Yes, definitely not needed when travelling inside the country.

Tod Daniels yes, that's exactly my point. But we needed this paper not to get fined in Chiang Mai, because we flew in from abroad and spent 2 weeks in Bangkok before reporting ourselves back home in CM

Everyone up in the north is quite serious about the rule. My hubby just had to ask for a TM 30 for a place he was staying in on a business trip in Bangkok (we're based in Chiang Mai) and gave everyone a laugh at the office until they realised he wasn't joking and they will have to pay a fine if they don't get one for him.

Yes, from the description and the comments above it seems that your school was just not aware that a Thai police check would be needed together with the home country police check after a certain period of time spent on the territory of Thailand. They will now have to wait for you to get it done locally and also call the embassy to see if they can explain the faults they found with your US police clearance. It might be also worth trying your luck in a different embassy next time

My understanding is that your wife's visa is not a guarantee (sort of) for her getting a work permit/extension (in the eyes of the embassy I mean). So her paperwork needs to be sorted out first, then her company will provide you some documents to support your application and then you get your visa. I haven't heard of the companies who would support people for both types of visa simultaneously

Well, this is what we did for my daughter (she's a dependent of my husband who is on a non-imm B visa)

Yes, I don't think you'll be able to get it straight away, unless you have the right documents from her company. Normally a person first gets a non-Imm B visa, then the work permit and the extension of stay and then spouses and children get the non-imm I visas plus extensions.

That's my password for most things! :-)

It took 3 weeks for me and I am not a NES teacher, so keep trying!

It's not the company but rather the MOE requirement for SA nationals, as far as I know