This seems like a lot of work for not a lot of reward. If you have never used LOCA before, I would suggest testing on a test piece. It is very messy and needs a lot of practise to do right. In this case, I would just buy a replacement digitizer online; that way you wont have any issues with glue seeping into your ipad and curing in weird places potentially damaging the machine.
Sometimes what will happen is the auto focus mechanism will get some grit in it which prevents the small motor from doing its job to focus the camera. Sometimes you will be able to fix this by removing the camera, inspecting it and using something like cyber clean (very little) to pull the dust out. Otherwise the camera will need to be replaced which is still only about 10$ if you look around on ebay.
With that particular model, it is very common to damage the little cable built into the LCD, you will need to replace the entire LCD in order to fix the cable issue as the cable is built onto the backlight of the LCD and is extremely hard to replace individually.
This truly sounds like the battery connection is not doing so well. I would check out the connection to the battery. If not, it could also be overheating. I would check your temperatures, for laptops you dont really want to see much more than 75-80c at the worst. Check the temperature profile, when youre gaming the temperatures will have a small-ish spike and slowly increase from there until it reaches equilibrium, if your temperatures just skyrocket you may have a thermal paste issue which will require you taking apart your machine and re applying thermal paste. Let me know how it goes!
Replacing the hard drive would be easiest. If you remove the hard drive from the machine and wipe it clean, then re install it to the chromebook and restore the original software using the manufacturers website you should be good to go.
In most cases where the IMEI has become unknown on other devices, it usually means the baseband has failed or has failed to initialize. I would start with a factory reset and update, if that still does not work there is a good chance the baseband is hooped.
You will have to replace the metal plate that has the flex extension in it. During screen removal, this cable is easy to stretch and subsequently damage. I did it on my first one and panicked because you cannot replace the Touch ID but turns out it was only the extension which is replaceable.
I would ensure that your ground connection from the battery is proper as a first step. My friend had an issue where his car would straight shut off when he turned the wheel at idle. Bad ground connection.