In my opinion one can't solely or 100% rely on footage from the show to form a theory. The footage contained within the series is always prone to continuity mistakes (which is why a continuity person is employed for all shows and films). Even so, many continuity mistakes persist nonetheless, and many more can crop up in the editing process as one of multiple takes of a shot is cut together with one of multiple takes of another shot where body position, props, and performance are not fully in sync despite best efforts.

Shows are victim to the writing and producing process, with many factors such as studio pressure and other projects affecting decisions (read: Heller's new show 'Gotham'). Within the canon of the show - the most logical explanation may be that Sheriff McCallister is a decoy, however, in reality we may just be seeing signs of a poorly tied up ending by a writer who cares more for providing what he deems the right thematic ending, at the expense of one that fits with the clues (which are often written in before the writers they decide how they will fit in later seasons -- remember the identity of Red John was only decided on by Heller during season 4 or 5 according to interviews).

Heller AND Baker have both confirmed in interviews that the plan was to tie up the plot and reveal Red John for fans before the show went off air and was at risk of not being picked up for another season, while also to use the latter half of the season to setup a new direction that would give the show the best chance of being be picked up again. 

Having seen great writers and producers ruin the endings of two iconic shows: Lost (of which most clues were ignored completely or were ret-conned) and Dexter (whose characters were bent into actions inconsistent with their fictional selves in order to service the writers thematic ending to the show), I wont be surprised if this is indeed the end of Red John.

One thing I would like to note however that I havn't heard anyone mention yet (possibly because I am mistaken - please correct me if I am) is that Lorelei tells Patrick about shaking hands with Red John BEFORE they get to the house in the woods where Patrick crashes the Jeep. After Patrick wakes from his concussion he sees Kirkland for the first time. If this is indeed the case, then how can Patrick put Kirkland on his shortlist?

What does everyone else think?