The first boot edition (flag 9), can be deleted if you won't use Windows Recovery by booting that image.
The second boot edition is needed for setup, as Clanger stated.
Note that sometimes I got an error that flag 9 edition is missing when starting setup.exe from the ISO (not booting), still haven't figured out when that happens. So keep that too if you plan on using Host Refresh or manual Setup.exe Windows Upgrades from that image.
To turn off UAC, disable the setting "Enable UAC - Filter all administrators (EnableLUA)"
So, if anyone deletes that Windows PE boot file, then the Recovery option will not be shown or use if anything goes wrong while using the OS, right
and about the UAC, can you tell us where can I found that 'Enable UAC - Filter all administrators (EnableLUA)' under which section, searched but didn't find anything, only found UAC settings under the Configuration/Settings option, attaching ScreenShot of my configuration i.e how I set up the options to disable UAC, kindly check & confirm if that's correct or anything that needs any correction in order to completely disable UAC.
Also, I have a few more customizations questions to ask
1. How to set the desktop icons view to the 'small icon'? I don't find any customization option for this on the latest NTLite version.
2. How to skip the 'Link your phone & pc' option into the Unattended OOBE/OOBX
3. How to disable the Cortana part completely, earlier in rs5 17760.1 ISO, I completely disabled all the Cortana settings while customising but still the Cortana art showed up into the Unattended OOBE/OOBX
4. How to set up the activity History options into the Unattended OOBE/OOBX
Also, how to enable dotnet3.5 by default via ntlite, is there any option to enable/integrate it since the first boot without manually download & install this after installation
Hope to get some help from you, thanks
nuhi