Hotspot Bar color?

RED: HOT
BLUE: COLD
YELLOW: NORMAL
GREEN:

What is green supposed to mean

And I dont understand the Defense lil bar. It turns red in the 1st 2nd or 3rd line, what does that all mean

It comes up when you press LT on defense, and this is how I interpret it. Please correct me if I'm wrong. 1st line is the line closest to the player your defending.

It indicates how you are guarding your man. 3rd line means loose, 1st line means close. You can also move the lines a bit left or right to try to force your man to go to his weak hand or into help defence. 1st line is useful to stop shooters, but it makes you weak against drives, 3rd line is better to stop drives but it makes you weaker against shooters. Basic basketball stuff, really.

and I have never seen green on the hotspot thing, but its probably the player starting to get cold.

what do you have to press to see the hotspots?

I don't think there's a button to see them.
On the 360 the controller vibrates once you stand on one of a player's hotspots.
Don't know if they made that comatible with the PC.