Let me expand on the Williams thing a little more, as I think it might shed a little more light on your question(s).
What Ted meant was that a hitter should be "guessing" the pitcher's next move before he even makes it (the pitcher that is)...and by "guess", it's as much as an "educated" guess as possible given the definition. IOWs, the hitter has already studied the pitchers tendencies before he ever steps into the box (unless he's the leadoff hitter at the start of the game), and becomes more "educated" wrt those tendencies as the game goes on (and this is if it's their first meeting, prior games and/or films are also taken into consideration if/when available).
So wrt to all of those clips, it is my "guess" that Miggy already had an idea in his mind what was coming wrt the pitch and location simply because of the count, inning, score, pitchers strengths/weakness (over his career and/or what is, and isn't working for him that day), Miggy's perceived strengths/weaknesses (which as W=w points out lean far more on the "strengths" than "weaknesses" side of any hitter out there)...then with all of that info (and probably more I'm not thinking of at the moment) determines/"guesses" what and where the next pitch will be, and adjusts his swing mentally for it.
Let me also say this. As you go further, and further up the ladder, hitting becomes more and more difficult, and the idea that a hitter can step in the box, and have some magic mechanics that allows him/her to be able to suddenly adjust for any pitch thrown is just nonsense shared by those trying to make you believe that IF you learn *their* mechanics...you too can hit any and ever pitch thrown to you at any time and/or any location...which is just not so.
Because if that were really the case, we'd never see a hitter swing and a pitch when they swung at it...nor would we ever see a professional hitter in 2-strike count just look at the FB right down the middle, never taking the bat off his shoulder, then tip his hat to the pitcher as he walks away thinking he was sure he was going to get the CB in that situation. IOWs, sometimes even the best "guess" is the wrong one, and you get beat...that's just the game, and why it's so much fun.
So I'm more or less saying that Miggy already had in mind the swing he was going to put on the ball/pitch...that he already had in mind before the ball left the pitcher's hand. Hope that makes some sense, and is what you were inquiring about.
Guessing IMO and experience has more to do with hitters getting into a leveraged position for the zone they're attempting to cover.. I am referring to a zone that will allow one to launch both the fb and off-speed pitch.. 2 strike hitting is less about hitting position and more about reacting to cover the whole strike zone.
Miggy, as well as guys like Mauer, gwynn etc. IMO never worked on launching from a leveraged hitting position but treated most pitches like they had 2 strikes.
