, with a bank account, I can do all these in 3 min anywhere in the world. There’s at least one food court that does not accept cash; only electronic payment.
, the buyer can transfer foreign currency for the purchase from an overseas bank account into the seller’s Thai bank account for the Thai bank to issue a Foreign Exchange Transaction Form…..of course this will depend on the level of trust.
You need a Thai work visa to be a real estate agent (and any other jobs requiring a physical presence in Thailand). There are lots of examples of people who have otherwise gotten in trouble.