Robertmap

:)I always replace the LCD screen of my phone and tablet by myself, which can save a lot of money.

I recommend the Lenovo Miix 630, which comes with a 4G module, you can choose it if you don't mind it powered by Qualcomm Snapdragon 835 processor. The list has more lightweight tablet and laptop https://www.myfixguide.com/lightest-laptops/

HP has launched the Chromebook x2 detachable , it has a 12.3-inch, 2K display and runs on an Intel Core m3-7Y30 CPU, 4GB of RAM and 32GB of eMMC storage.

You have better choices. For example, you can choose Skylake Core M or Kaby Lake Core Y processor. Its performance is better than that of Pentium and Atom. this list have a lot of 2-in-1 laptop, please check https://www.laptopmain.com/fanless-laptops/

I suggest by original HP battery or well known brand.

Hi, you can search it on ebay.