Oxford to do HistoryWatch
Also Formatting!! Why the wall of text?
Your over thinking this to be honest, Nobody (not even me) can tell you what your statistical data will be should you apply, since some of it is based on yearly cycles.
As I said before, the HAT is an important part of the process, if you want to apply to Oxford you would be foolish to not revise for it. The odds for gaining an interview off the back of that are high (3/4 of applicants get an interview for History) which is a very high amount.
Have you been to Oxford to visit/open day?
I would strongly encourage you to do so before you do decide to apply.