1.) This isn't always the case, especially if the woman has an open-minded disposition. I've been friend zoned many times by guys who were far more apt to share personal and intimate conversations with me than with those they were intimate with.
The direction of the conversation is key. If the topic is more generalized or seems to focus more on his own problems (as though he's being diagnostic toward himself) chances are he's merely looking for a sounding board. If he focuses more on your specifically, then he is showing interest.
2.) Men, just like women, do not exhibit signs that are 100% foolproof. They will have to be taken into context. Also, almost any sign can be faked in an effort to bait someone. Time is pretty much the only factor that can show if his intentions are genuine or not.
3.) A player will typically have a very generic view of you... he'll remember very few details about you, or may avoid topics involving you in great detail. He may talk more about what he has to offer or pick a topic that interests you greatly and is easy to follow and won't stray far from that. It's the guy's mission to get in your pants -- not learn your whole life history.
A guy who is really interested in you will offer a conversation that is more give an take... he'll share some things about himself and then wait for you to share some things about yourself. He's genuinely interested in you and is looking for some common ground. Getting laid isn't his immediate goal. Determining if you're someone he would want to be around (and possibly lay at some point) is his goal. He wants to know if he really likes you and vice versa.