Most of it is supported on the wiki, the rest you can ask about here, but no there is no comprehensive list of meanings for every character and every character state and color. A lot of the colors of materials, objects, and terrain depends on what that stuff is made out of, and also depends on time of day/night, where at night most everything takes on a deep blue/dark gray hue.
For the blinking creatures, it could be a facet of the creature (some of them are just set up to blink), be trying to tell you there are multiple creatures on the same tile, or the current status of the creature. For instance if they are quickly blinking a red or yellow + on a white background that represents injury, with red being more severe. The pink things in rooms you're no longer in represent the creatures you saw when you were in the room at the location you last saw them. If you go back into the room and they've moved, then leave again it will display those characters in the locations they were when you left the room. Items also appear on the floor as a dark green after they're no longer visible.
I dont think the ascii facet of the gui is ever going to change, that's just how the game is meant to be. You'll always have to view a separate window to find out exactly what something is or its exact status, because more blinking status characters will only be a bigger headache. right now the controls and everything are more or less standins just to make it possible to play at all, things are still being worked on as we speak. It'll all happen eventually.