are u applying for a non o cause of ur going to retire in Thailand ( over 50)? If so just apply for a single entry Non O visa ( valid for 90 days) and once in Thailand get a 1 year extension..
no Medical, no police clearance,no bank books needed
If ur stamped in on one passport and have a new one, take both to the border, u'll be stamped out on old one,enter laos on new one an get ur new visa in new one>> easy..