Bruno Heller once said that "Red John ultimately is just a man - - -  I can guarantee that people will be
disappointed." Now the story underlines Gail Bertrum as Red John, but he is the biggest boss of the suspects. With that ending people would not be dissappointed. Sheriff McAllister on the other hand is just a sheriff of some distant area in California and he was only in the pilot episode and mentioned nowhere since before the end of season 5.

Bertrum tried to kill Jane, because he was the only one who knew that Bertram is dirty. Sure Reece Smith knew that too, but without Jane everyone would have believed him as Red John. And Red John telling Bertrum is dirty cop would not mean anything. But now that Jane is awake, Bertrum needs to run and it really does not matter if he kills a bartender or not. I think Jane also knows that Bertrum is not Red John, but he is armed and dangerous and on the loose. So it is good to warn people about Bertrum and at the same time the real Red John thinks that Jane is chasing the wrong person.

Partridge is as dead as he can be. How could he have faked his own death unless he had a twin brother who he killed. Red John put someone in Blake Association to remove the piece of skin from his shoulder to make people suspect that Partridge would have faked his own death and that Partridge would infact be Red John. The tattoo was removed but a cleaver guy could not say if the tattoo was removed or the skin was removed to make it look like the tattoo was removed.

McAllister placed that bomb and faked his own death. He was
identified from a DNA. It's fairly easy to leave a piece of own DNA to
the crime scene. As a member of Blake Association he had the power to do
things that looked like he was a big boss in CBI/FBI/wherever and that
same thing helped him to make things look like he had moles all over the
law enforcement. He is Red John.