Do not afraid. I have got the same experience :) Let God bless the search button :D
adb push fbmode /data/local/fbmode
adb shell chmod 755 /data/local/fbmode
(1) If I update to 2.2.0, will my settings be wiped?
For sure. Wiping is one of the main prerequicities for stable ROM working
(2) Is the any difference between updating via auto update and download then flash?
Yep. Custom ROMs/Kernel have no...
In phone application, Phone section enter
phone info -> SMSC -> edit and update