I really don't think Crono = Miguel. I've heard both sides of the argument, and this is why I believe Crono =! Miguel.
First off, look at it from the game production point. Let's say that in the story production, they put in that they are the same person. Now obviously, you're going to have to put in a ton of clues, and USUALLY something that pretty much spells the whole thing out for you.
In my opinion, CC doesn't have any of this. There is no dialogue from Miguel that even does so much as suggest that he was ever a fighter, came from the mainland, anything. It seems to me that any theories we have about him are based on assumptions we're making on other assumptions. For example, we're assuming Crono is alive, not dead. We're assuming he went into hiding, and is not in prison. From there, we're assuming he travelled to El Nido, assuming he took an alternate identity, etc etc. There is no actual PHYSICAL evidence in the game that any of this hapenned, so we're basically drawing conclusions based on "false" conclusions.
Obviously, I have no problem with people thinking that theory, I jsut personally don't agree with it, for the above reasons.
Also, Kazmaka, isn't most of your "evidence" from just reading around on the boards? Because you still haven't played Chrono Cross, and no matter how much reading you do, you'll never be able to really understand what's going on until you play the game and put it together.