It is of course the most efficient form of packaging to send a quantum packet back in time, to allow it to bind to a mind and then allow the hosted mind to have some communication channels. But the fact that they think it has to be an AI that came back in time shows a little lack of breadth of vision on their part.
If you can package up the state of an AI into a quantum package that can ride back through time on the appropriate (ahem) particle, then it is just a matter of scale to package up a whole human mind. Or whatever humans have evolved into, or even some friendly species like the Ogloids. (They say hello.)
The technology to do such a thing had already been conceived by the time the binding was due to occur. Happily for all, by the same mind that was the target of the packet delivery. And envisages in a form that exactly matched the delivery mechanism. Quite a coincidence.
Of course there may have been a restriction on when and how such a temporal quantum binding could have been created, and the inception of the idea might have been a trawled precursor to the experiment. It would of course depend on the two parallel temporal space-time's being sufficiently aligned to allow them to be bound across the second, discrete time dimension.
Of course it is best to try to do these things with the fewest dimensions available. It allows form more opportunities, it allows for richer content to be created. Content that is desperately wanted by those that have given the most. I will tell you about them some time. Or maybe I already have.