John, Bath's do not necessarily need their own circuits, but any outlets in the bath, along with any lighting near or above sinks/tubs/showers do need to be GFCI protected.
-It's nice if you can put your refrigerator on it's own circuit; 15A will do if it's dedicated.
-Dishwasher & disposal paired on one 20A circuit is quite common. Your dishwasher is required to have a service disconnect these days; usually done with a standard wall switch in a wall box inside the sink cabinet. Use a double box, and you can put the dishwasher switch and disposal outlet in the same box.
-Even though it would just be one light, better to keep your furnace completely separate.
-If planning to upgrade to a new breaker box, now's the time. And yes, FedPac boxes do have that reputation.