There are many reasons, known and unknown for a dog to develope immune mediated hemolytic anemia. Vaccines may be one of them but how to tell if it is the cause? I have no clue. Vaccine schedules less frequently is an option or none at all after the first few years might be an option. But if you remember when parvo broke out or even longer ago with distemper, vaccines do have their place, just not as often is the dose necessarily needed these days.
AS to the rabies it is the same vaccine used for 1, 2 or 3 yr vaccines but the state regulations recognize the length as to the protection afforded to the dog is different from state to state. Michigan has a 3 yr, Texas is 1 yr, I believe.
