I think the better solution would be to turn off the stress causes aircraft damage setting in FSX. I saw it suggested somewhere else on here because of REX making turbulence more substantial than the built in weather engine did.
What makes my ENBs different from most others is the ENBpalette.bmp files is what actually controls the dynamic lighting. The settings in the ENBseries.ini file won't have an effect on image brightness because of the palette doing it, but you can tweak things like bloom.
24 Hour mod - My first one. Goal was to make more realistic lighting that is dynamic for any time of day. Main things are when looking at the sun makes it harder to see the panel. Dawn and dusk look more realistic. At night darks are even darker and lights are brighter.
VFR Mod - A more refined mod based on the 24 Hour mod idea. Still good for all day but really intended for the day period in VFR conditions. Makes it more bright and sunny, also does some color enhancement to make the scenery look more lively.
IFR Mod - Enhances cloudy IFR conditions, makes it look even hazier and evens lighting to make a realistic overcast feel. Also good for night flying, instrument panels aren't as bright.
I looked at your joystick setting image from FS and they can't be helping. The null zone is basically how much of the controller range is considered to not do anything as if it is perfectly centered. Usually the null zone is just a very small amount so that you don't have to be perfectly centered to have neutral controls but then when you do move the joystick it goes out of the null zone and it takes your control input. The sensitivity for the various controls I have used are usually around the half way mark.
You should also click the calibrate button to bring up the Windows properties on the device. There is a screen that shows where it is interpreting the position of the control. If it doesn't match up to the movement or current position that will make the problem more obvious.
Not sure about your issue but looking at the video I can tell that their camera is zoomed out a bit because of the distortion to the scenery close to the screen edge when looking around. That gives an appearance of greater speed. It also looks like it isn't in real time because of the how abrupt the movement is and the unrealistic acceleration on the runway like it has rockets attached.
It actually is an angle of attack indicator. The reason you think it doesn't line up with what it is showing is probably that your understanding of AoA is off. It is the difference of angle between relative wind direction and the chord line of the wing. The chord line is from the center of the leading edge of the wing to the trailing edge of the wing. The chord line is going to be higher at the front edge than it is at the back, otherwise the wing would not produce lift, so this line is already angled upward at least a few degrees in relation to the body of the aircraft. If you are flying straight without gaining altitude, your AoA is still going to be somewhere around 2-3. If it was showing 0 then the wings won't be creating lift so you will start to descend. If you could hold the plane at that exact pitch, the AoA would eventually increase again because the relative wind direction would be coming from a lower angle.
Hopefully this helps, it's kind of hard to explain with only words. You can get an idea by doing some maneuvers in the 737, just leave your passengers behind.
As for your other question, I can only go off what I've found online. It seems to be due to colder air temperature at higher altitudes and speeds being based on mach numbers because the speed of sound is slower in colder temperatures.
Like this? The KCMW looks "wonky" because it's the built in tail number from FSX applying it to the model. Because of a bug in FS it isn't possible to hide the tail number for default aircraft so the only way to not show it would be to not give it one which would then cause ATC to sound off.