Brett
If he faked his death the body should be ash already when Cho went to check it .. he can not take the risk by delaying the burn of false body.
How he can be sure he will not be identified as a live?  and the body does not belong to him??? 

Reede
I guess we all agree he is out

Gale
from the last episode: very unlikely

Bob
confirmed dead by the blakes

The bomb and the three bodies
DNA Plantation is not impossible and has been used by much less smarter than red john. However the blakes can easily mess with the report and the DNA matches.

three bodies became "crisp" while Reede clothes are not touched!!! forget about Gale and Jane, they are a bit far

the gun shot happened long before the explosion, so it has nothing to do with it. Lisbon didn't hear it and Jane knew what happened. That's why they didn't ask Reede about it  

I'm  guessing Here:
Some one tried to act .. Jane tried to shoot. Most probable the one raised the gun and the shot was on air. the situation got out of control

Red john (I assume Ray) has brought the bomb in a box together with three bodies ... during the mess he activated the bomb and disappeared together with Tom (The highest rank in the Blakes) and Bret (first Mentor)

What do you think??