Okay, I'm not taking credit for this because I read this on one of the threads last night. Someone had mentioned to turn off the inbuilt iOS Facebook account in Settings. I did this last night and charged the phone all night long. Took it off the charger and used it for 15 minutes. Happy to report that in the 15 minutes of use the battery did not drop by a single percentage point.
I will continue testing this all day today and report back. If anyone else is willing to try please give it a shot.
Edited to add:
By the way, I had noticed that my phone would continue to have usage times even when it was in standby. For example, yesterday it showed 18 minutes of usage time over 4 hours, even though my phone was in my pocket the entire time. I have already taken the standard precautions of minimizing notifications, push, brightness, location services etc.