Intl Departures 2 after security check when you go down the escalator to passport control turn right you will see the sign re entry visa. If you use Intl Departures 1 you get stamped out and tell them you need re entry visa they will make you walk to Intl Departures 2 and get it. The latter is after passport control. So don’t worry either way is fine, I’ve done both.
Open Krungsri or Kasikorn bank you can transfer money from Thailand to uk or anywhere else directly from the app on your phone pretty straight forward. For other questions you got plenty of answers.
muai Thai could be an option, or a language school, but probably exit and come back on no visa required the simplest, in all cases need to restart the process from scratch once you know what you will be doing. Very important once the current Ed visa expires you must go to immigration to cancel it if you don’t renew it or they may face issues or a fine with the new one once they are back.
So what you are saying is that the present school is ending the term
and consequently the visa when your son will effectively leave the school and the new one will not issue a new letter because you have not signed him up as you are still uncertain whether you will stay in Thailand at all, and this is a surprise? Anything else would have been illegal, in case you are wondering…. Basically the old school would have given you a letter confirming school attendance when there wasn’t one just to assist you in the transition that you are still undecided about? I’m afraid you are out of options other than having wife and child leave the country and come back on a no visa required (depending on the nationality) extend for one month and then start the process all over again once you made up your mind. Or depending on what visa you are on have them be your dependants. Not many other possibilities I can think of.