As you have stated and reinforced by the links you provided, it sounds as if a production run of these devices were not given a quality control final check. This does happen often on phones, and you can replace them but only within the 14 day period (if you got it from a carrier), but if you are beyond that time frame then you will need to contact LG about it. However, it is possible to replace nearly everything on the G5, and this does include the buttons. Take a look at the photo provided in the iFixit teardown: https://d3nevzfk7ii3be.cloudfront.net/ig... On the left, you can clearly see that they have removed the fingerprint scanner. This replacement is possible but I would not go through all of that work just due to a rattle. If the rattle became worse and the button started to slip or give inaccurate readings, then I would contact LG for a warranty claim. If you do the repair yourself or have a repair shop do the repair for you, it is possible to tighten it up if it is still a bit loose. Each person...
If you are going to be using a display assembly that is not already adhered to a midframe, then it does not matter as these display assemblies (when off the frame) are not carrier specific. You can get any display assembly and install it without issues.
The Asus gaming laptops (and all of them, really) get hot. It's just what they do. Now, if it is abnormally hot, which it sounds like it is for your case, then the laptop needs to be taken apart and cleaned. I just repaired the same model for a friend of mine, and it was filthy on the inside, even though the person themselves was a clean freak. The fan ports on the laptop get clogged up easily and quickly, so a good cleaning should help out a lot. I highly doubt it is your fan.
Itunes error codes are about as useful as a football bat. You can google the supposed fixes but they are usually always a board level issue. You can try a different cable, a different USB port, a different computer, a different charge port, and so on. Yet, none of these never seem to solve the issue. At this point, you should either take it to a repair shop, or to the Apple store.
There could be several reasons your laptop is getting hot. First off, laptop is a bit of a misnomer--they get hot and are meant to be used on a desk. Secondly, this laptop is a good 7 years old at this point, when was the last time (if ever) it had a thorough cleaning done on it? Start with the basics and clean it out, new thermal paste, etc. Then if you are still experiencing abnormal heat issues (ie, burning your flesh), then there are some other issues at play here. If it is heating up after 30 minutes, though, probably needs a good cleaning.
Hi Sasa, Has your phone been worked on before, such as a screen replacement or anything else? It sounds like a boot loop caused by board damage. I've had a 5S come in for repair doing the same thing you are describing. Please let me know what type of work this device has had performed on it in the past. If no work has ever been done, and if you are sure the device has not been opened before, then did you purchase this phone new or refurbished?