The good news is that Chiangmai Immigration have English-speaking and friendly officers at the Info counter. If you have time, drop by and ask them directly.
Schools will arrange ED for kids whose parents do not have a valid permission to stay, which then the parents will tag onto for their Non-O. Not needed in your case. Do note that all of you will be dependent on the validity of your husband's permission to stay.
’ reply below. If you check with the school and they can provide you the documents to convert a visa exempt entry into a Non-B, I’d go with that. But if they can’t, you need to weigh delaying your flight against having to make a trip out to a neighboring country.
If you fly here without the Non-B visa, you will have to make a trip out to a nearby Thai embassy/consulate to get it. No possibility of delaying your flight until it’s settled? You aren’t allowed to start work without the correct visa anyway.
If you were not asked to bring in your bank statement for verification, you only need to turn up with your passport and if you have one, a TM30 receipt.