Screen distortion, flicker, colors

Hook it up to an external monitor. As you are not mentioning backlight problems (besides flicker), a good picture there will help narrow down the cause. I believe you will have a good picture there. Protocol says to start there, is why I offer that suggestion.

On this model of MBP the wires carrying the voltage for the backlight are incorporated into the LVDS cable. The screen flicker along with other video issues suggest there are problems with the LVDS/video cable. The fact that moving the clam shell towards and away from the keyboard can resolve the problem, not mentioned, or create the problem enforces that the issue resides in the video cable. The cable does run through the bottom of the upper clam shell. Since pressure on the lower portion of the clam shell can resolve the problem that points to the LVDS cable. The LCD controller board and TAB (Tape Automated Bonding) are in the upper part of the clam shell.

Prior to purchasing a LVDS cable I would see if moving the screen toward and away from the keyboard to see if it also creates the problem. If it does I would remove the bottom case of the laptop and battery connector. You need to remove the battery connection so it can't spike anything. Try reseating the LVDS cable and see if that solves the problem. A poorly seated cable connector can cause the same symptoms. You may also want to lay the opened laptop on it's side and while powered on move the cable slightly (not enough to disturb the motherboard connection) with a pencil. If that solves or creates the issue(s) you know it is the cable.