I can't honestly say what the problem is, however maybe try using a virtual machine for Windows 10 rather than dual boot maybe? You will see a difference in performance. However it should have no problem with restarts and what not...
If it was the graphics card that was the problem, then when you're mirroring to other displays it would show up there as well. However overall, the problem sounds suspiciously like the LCD is damaged. If you have Apple Care, Apple may cover it. Otherwise you're best bet, price wise (Apple 'aint cheap to fix stuff), is to go to a computer repair shop or consider a new computer. Because usually these problems get worse over time. I had a similar problem with my Macbook Air (same model) but my case was far more pronounced and the screen changed colour severely with the computer needing a new screen. Again, Apple will charge a lot. But Apple Care will take care of the problem if you have it.
Recheck that you completed step 15 correctly as that step deals with the display data cable. If that isn't connected properly then your display won't switch on properly. Otherwise it might be that you cleaned an internal component with a static electricity generating object (a synthetic brush maybe?) this could have disrupted any number of components.
Do you have any wireless routers, microwaves or metallic objects positioned anywhere near your console? These can disrupt the signal or wireless controllers. As far as plugging it in to play that only works if you use the play and charge kit. Which asks you to connect the battery pack to the USB cable and that to the console. If after all of this still nothing is working your USB ports may be damaged, or the console itself may be damaged. If you can also try using friends controllers to test whether or not it is the controller that is malfunctioning.
I have had a similar problem, with my Macbook my charger looked like it was working, and the SMC reset went by with flying colours but it would still not switch on. My advice is that it could be a logic board failure like you thought or it could be as simple as a dodgy charger. Mine had lights going and the mac power 'brick' would eventually heat up as normal. If you can try testing your computer charging with a friend. Otherwise it is most likely a logic board failure.
Some Kindles can be affected by high amounts of electromagnetic energy, such as airport security. If you've been anywhere near these kind of things then you're going to need a new kindle. Otherwise the hard reset (holding down the power on slider for 20 seconds) should be of help in fixing it. Try it a few times as some people have found that it can take a few goes.