Regarding 2nd point, i too experience the same problem, phone doesn't switch to 2G network unless the 3G signal is very weak.Hi,
i tested Oreo build (from september 23) and here is what i found:
1. LED is not working when power connected. (no any color)
2. Always H indicator is shown, no matter 2g or 3g is active.
3. I deleted system Clock app but alarm notification is still displayed in notification line.
4. Sometimes WiFi blackouts are happen...but it's known issue
5. Some of ringtone, notification and alarm souds are duplicated.
Must say this build is very stable, regardless to some SoD, and i like performance level.
Hope my feedback will be useful.
If I found something else, i will notify you.
Sent from my Nexus 4 using Tapatalk