Activation Lock Removal - iPhone 4s - iOS 9.2

My older sister gave her old iPhone 4s to me for Christmas. It was working perfectly fine but I wanted to be able to use my own Apple ID (credit card and purchases related ultimately) on this new iDevice so I tried to log her Apple ID off. The iPhone required me to enter her Apple ID password which when I asked, she does not remember anymore.

I then tried to restore it on recovery mode using the instructions provided by Apple Support and this is where my problem started. After the update, it apparently still needs the old Apple ID and password. Now it's stuck on the Activation Lock page and I can't use it at all.

She tried to recover the password using her recovery questions but she's only been able to respond correctly to questions with concrete answers (her birthday).. The other questions look like "What is your favorite car that you've owned?" and she knows the answer but not certain whether she put the make and model of the car or the nickname she gave it. "Where was your first vacation with your spouse?" but she's not sure whether she put the name of the province or the island or the name of the resort. The worst thing is that the email she used wasn't a verified email and is now gone.

I have now scheduled to receive a call from an Apple Support representative. My question now is WILL THEY BE ABLE TO REMOVE THE ACTIVATION LOCK IF THEY WILL SPEAK WITH MY SISTER AND SHE CAN VERIFY HER INFORMATION AND IDENTITY AS THE REAL PREVIOUS OWNER?

I need real answers so please do not tell me I'm d*mb or anything like that because I kind of actually feel that way already.

I need helpful answers.

Thank you.

Message was edited by: steffaller