I did not mean to berate you. If it came across that way, I apologize. However, people who have spent enough time diagnosing computer issues, either professionally or for personal use, have come across hard drive issues similar to yours and in most cases have come to realize that the most optimal solution (time and aggravation-wise) is to just replace the drive rather than investing more time and effort with the old drive. That's the message I think most of us are trying to convey.
I don't see the results from the DriveDx software (was it in an earlier post?). So don't take any lack of help on that as being a criticism of your efforts.
As I recall (correct me if I'm wrong), this computer isn't under warranty, is it? If it is, then being informed about various diagnostic programs say may help when conversing with a technician. If it is not under warranty, then really the cheapest and easiest thing to do (diagnostics will usually cost money) is to just tell the service shop to replace the drive.
I have the same model of MBP you have (although it was manufactured late last year). The main problem areas for the this MBP is the SuperDrive (DVD), normal wear of the HDD (which makes sense in your case) and the HDD cable. Otherwise, these are well-built laptops and other than these components, the computer should have a life span of years to come. Over-heating can be as much of a software issue as it is a hardware issue but the only way to know for sure is to be able to monitor it when it happens. If overheating happened at one time but is no longer happening, it's not likely to be a fan problem. I think the best advice is to replace the HDD and see if you still have problems after the replacement.