I start at ATP June 11th and can give you the inside scoop from what I have gotten from EVERYBODY I've talked to.
1.) The CFI job is not a guarantee as you still have to meet certain requirements prior to be hired. Multiple checkride failures, can't pass a background check, etc. can all disqualify you.
2.) One of the CFI's I had to do an admissions flight with said he makes 1,800-2,500 a month.
3.) You don't hang around the call center for a few months. You will work there to answer questions while you are going through their CFI standardization program. Upon completion they will offer you a location which you can either accept or decline. If you decline and say you want Vegas you can work at the call center or another center until your seniority number comes up.
3.) If you do get stuck in the call center they will let you fly with time building students to maintain proficiency in the Seminole and also put those instructor certs to use. Most importantly they understand you didn't join their school for the call center job.
4.) There is potential to stay longer if you want although it isn't a guarantee for everyone.
Any other questions and I will find it out for you. Those were most of the questions I had before I even considered going there. All this info has come from either the Chief Pilot, Director of Admissions, or from the Assistant Chief of the Craig location where I am going.