This is to the degree of wild conspiracy theories; however, this whole Cuba incident defies all explanation. Sonic sounds plausbile for other reasons, such as the locality of the phenomenon (the victims didn't experience the effects if they moved). However, let's face it: sonic attacks are. just. impossible. There's E.T. It's never E.T. Furthermore, why would E.T. attack political officials in Cuba for, so far, no fallout effect? Poisoning? That doesn't explain the locality of the effect. Microwaves? Some people were in rooms, we can assume that they were shielded by concrete and microwaves aren't known to have these effects without other effects presenting more severely first. Gamma rays, or some beyond-gamma emission? Particle accelerators aren't that portable.

When I first heard about this I basically gave up on all explanations after things started becoming too crazy. The simplest explanation I have right now is a combination attack - you poison officials with "something" and activate it with some combination of other triggers (including sonic, as we have the recordings you linked). This explanation is full-blown Fringe and I don't like it for that reason, but this is really starting to defy all simpler explanations.

I really don't know what to think at this point: it is becoming science fiction.