Actually, (SPOILER)This theory is indisputably correct. Well, the first part. Mrs. Hawking's first name has been revealed, as it was during the "enhanced" version of "The Lie" that got shown immediately before this one. They identify her as Eloise Hawking. So, yeah, I don't know why they dropped the ball and verified this theory. Though I was pretty sure of it, anyway. The way they characterized Mrs. Hawking had her share a lot of mannerisms with Daniel in that last scene of "The Lie." No idea about Widmore being the father, though.
Also... obviously, Locke speaking to Richard right now in 1954 is what leads him to visiting Locke at his birth and then in the early 60's to test him for that school. According to what we saw, Locke failed that test by choosing the knife instead of the compass. Maybe, that sealed Richard's conclusions. The compass wasn't Locke's. Therefore, Richard had to give Locke the compass in the future, which validates everything that Locke told him in 1954.