I'm not laughing at his post...., this is a professional pilot requesting help from his colleagues because he knows exactly the same about contract through an agency flying as you did before you got involved with it..., which is nothing! So in the same way somebody took the time to explain it to you, maybe it will be more appropriate to share what you know instead of a junior high response.
How do you know if all the paperwork you've sent in is complete. I have not received anything other than they've received it. How does one know if it's complete?
The first thing you need to do KAP is not to assume that an agency is on top of things or that they are "in the know" of how your application is going..., they are NOT that organized nor vested into personalized service...!
The short answer is that you don't, so you have to follow up and be on them to make sure all your paperwork is complete because things fall very easily through the cracks...! If you are interested in a particular airline, be proactive with emails, calls to follow up on the status of your application.
* Is the paperwork automatically sent to each airline you've expressed an interest in flying with?
No, the system is not that efficient at all...! YOU have to do the legwork and most of these agencies will accept your information on their site but not do anything with it! most of the time these jobs require you to click to apply to each one of them...! It is frustrating I know..., but a lot of times you have to input the same information on each particular application that you spent a few hours downloading into the agency's site.
* Is it more the airline itself or the contract agency that decides who will be invited in for the interview?
The airline...., the agency would filter those that don't meet the criteria etc. but the airline is the one that calls those they want to see. Some agencies have a prescreening process to try to save money for the airline and filter the guys that can't chew gum and raise the gear at the same time, but out of the most desirable candidates, the airline makes the call.
* Lastly, to verify a pilot is with one particularly agency, is there an "id number" or some such associated reference or registration number that the pilot is supposed to receive identifying him/her with that agency?
Not sure I get the question..., You mean after you are hired?
Not that I have seen.., at least on my experience it has been just an employee number assigned by the company and not by the agency...! Not sure if I answered your question or not....????