The way I see it, the Hamilton thing is a red herring, otherwise it is too obvious. I have the feeling they intend to play Hamilton as a bit corrupt, always on the fence, but not really too dangerous or evil, and there may even be a redemption arch in the future. Let's see!

I lean toward Hamilton doing this, after all Garcia made it clear he had dirt on Hamilton. All we heard was that a car bomb killed Garcia. The question is, was Garcia alone? Was he the only victim? If no WITSEC agents were killed, it is more likely that Isler could be suspect, too. If agents lost their lives that would be all on Hamilton.

Very possible. But on the show's facebook-page there are quite a lot of people who are leaning towards Isler and not Hamilton. In some ways, that makes sense. Isler is more of an expendable character now that Garcia is dead and Gregorio got fired from FBI and is about to join NCIS. Hamilton will probably stick around and keep being a frenemy to Pride.
I've got nothing against God, it's his fanclub I can't stand

Hamilton behind this? I wouldn't be surprised.

Garcia maybe?

Santiago?

He was afraid that he would throw him under the bus, Garcia told him "I go down, so do you" (paraphrasing) so yeah, he did. which is what Pride wanted.

Or tipped off the cartel at least?