A very good theory, if I do say so myself. Someone's mentioning of Phantom Hourglass got me thinking, however. The ending of Phantom Hourglass is of Link and Tetra waking up ten minutes after the events of the game. Right before they wake up, they meet the Ocean King, a large whale.
Now, let's look at Link's Awakening. After the events, Link wakes up to find himself on his raft, which is supposed to be destroyed. He meets the Windfish, a large whale.
Since Termina is Hyrule's counterpart, and there is almost a doppelganger for everyone (excluding Link, Zelda, and Ganondorf, but you can prove me wrong), then what about Lord Jabu-Jabu? He is a large fish, possibly a whale. Maybe he is has a counterpart in Termina we do not know of.
Coincidence? Maybe. Possibility? Definitely.
It is possible that there are three timelines, one for each Zelda "category" (Child timeline- SS, Oot, MM, TP [the more serious]/Adult timeline- WW, ST, PH [the more comical]/Other timeline- MC, FS, FSA [the more cartoonish]). For the child timeline, the "dream" could have been Majora's Mask. For the adult timeline, Phantom Hourglass. For the other timeline, it could be Link's Awakening.