Seems they are prepared for this. Someone I met had Thai handwriting on his visa, I didn’t.
Google translate showed the writing noted that passport expires before visa and to allow transfer.
They will be especially aware as dependents are part of the visa. Children are only issued 5 year passports (well in UK - I don’t know all countries!).
Burma has one boarder open. Kawthoung. You get a speedboat or long tail from Ranong. You are given 20 mins in Burma and back to Thailand. Needs to be arranged through an agent. The idea of flying I think is best for you.