I don't know a lot about M.2s, but is yours besides your graphics card (If you have one)? The exhaust from the card will head up the SSD regardless if you have a heatsink or not.
It highly depends on your case. Mine 3.5" can hold every standard 3.5" and down, my 5.25" can hold anything 5.25" and down.
If the screws are in the standard position, I don't see why you can't.
Mate... The 3.5mm jacks on the motherboard are audio jacks, not analogs...
You need to connect the HDMI cable from the graphics card to the monitor directly.
What did you connect the HDMI in? The motherboard or the graphics card? That's a common mistake people do.
And what do you mean by connect the RGB and nothing came up? What is the RGB you are referring to?
Try to boot it up with your USB key, see if there is a language setting somewhere.
Because I don't think you can change the setting by replacing the files.
Since the past 5 years, not so much. The tech has matured. If you avoid bad quality/ brand PSUs, they are as reliable as today's PSUs.
Past 15? Yes. Today's PSUs are far more reliable than 15 years prior.
If they don't have a Chinese option available in settings, you can't change it to Chinese.
Still, if you absolutely want a Chinese password reset software, just go search it on Baidu or something. There are tons of it.