1. That means Mi5 gets special updates managed separately from other devices. So, common weekly changelogs are not affect to Mi5 devices. There is no separated changelog for Mi5 as there is no officially.
2. Linked MIUI8 v.8.0.10 is stable release for Mi5
3. TWRP included but you have to install SuperSU separately in order to get root on your device
4. sMIUI is modded ROM based on our releases pls find dedicated thread if you are interested in.
5. Developer releases get weekly updates, but full ROM must be flashed manually via updater app or via TWRP
If someone is worry about privacy issue because push notification from browser. Freeze it by titanium or lucky patcher and temporary use much better one like Gelo mod or if you have qualcomm device then for you there isn't better then Tuga browser. Both you can download from xda.