I think we may have some fairly strong proof that Doreen is in fact the intelligence behind the pendant. From the "Crono Foreshadowing" thread, Jerky pointed out that on Death Peak, the pendant reacts when the party uses the Time Egg. The egg shatters, there is an eclipse, and the part goes back in time to save Crono. If I am recalling correctly, the Pendant appeared to put energy into the time egg before it shattered.
We might notice this behavior again in Crono Cross. In the Hermit's hideaway the Masa and Mune react to the time egg that Kid has. They put their energy into it and the party travels back in time to save Kid.
In short, in CT the pendant played almost the exact same role as Masa and Mune did in CC. While the pendant might just happen to be able to produce similar effects as the dream species, it seems to require less random leaps of faith to suppose that the pendant reacted similarly to the dream species because the pendant is part of the dream species (aka, it is Doreen).
To note, however, Kid’s Time Egg is clearly not complete, while Gaspar’s Time Egg presumably is. However, to be fair, this wasn’t clearly stated. Indeed, even if Gaspar’s time egg was completed, it still might have needed an external power source (hence, possibly why he said that the more effort the party put into their quest the greater the egg’s outcome, and why the party had to climb death peak, a place of power).
