You can find a small vacuum leak in your 2002 Toyota Camry with a diagnostic tester. The diagnostic tester can pinpoint virtually any vacuum leak.
You need to replace the oil seal.
To answer your question; I would say your Freon is low and you need a recharge but it also tells me you have a leak somewhere.
There is not enough information to answer this question
The Camry could have a vacuum leak. If there is a vacuum leak, then there can be a whistling sound until the vacuum system is full of air.
Oil can either be burned, or it can leak
Shampoo the engine to clean it. Check for leaks in a day or so depending on how bad the leak is. Replace the component causing the leak. If you still can't find the leak you can put dye in the engine oil and look for the leak with a black light.
Yes it is, you have to get it looked at ASAP.
You do not have many choices either replace it or if the leak is not sufficient buy one of those leak fix bottles.
That isn't much consumption.. If it buggs you take it to a garage and have them give you an estimate.
You don't. If it needs refrigrant, it has a leak. Take this to a professional. You have neither the tools nor the expertise to repair.
Low coolant level, internal or external coolant leak or faulty thermostat.