Is any leaking, say from a leaky valve cover or dripping from a worn seal? How old is the PCV valve? If old or age unknown, change it. If that doesn't help and there are no leaks then oil consumption is likely due to engine wear, in which case the best approach will be to continue adding oil as needed. (Some new cars even consume that much oil and manufacturers claim it's "normal" and won't do anything about it.)

Heater problem could be anything from a clogged heater core to air in the cooling system to thermostat stuck open to the HVAC controller and temperature blend door being faulty. Needs to be scanned with a professional-grade bidirectional scan tool. As a quick test, warm up the engine and turn on your heat. Both heater core hoses should be hot if not clogged.

Besides what @Chuck Tobias mentioned, you can do the dry and wet compression tests to see if the piston rings are worn or not. That's an old engine with high mileage and if the oil was not changed frequently, you might have issues with the oil burning.