Explanation/Reference:
B: Add a Customized Script with Winpeshl.ini
You can launch a customized shell application by using a file called Winpeshl.ini. Winpeshl.exe will process the settings in Winpeshl.ini during boot. If you create a customized Winpeshl.ini and require Plug and Play or network support, you must include a call to Wipeinit.exe. Wpeinit.exe specifically installs Plug and Play devices, processes Unattend.xml settings, and loads network resources.
C: Add a Customized Script with Startnet.cmd
You can add customized command-line scripts in Windows PE by using Startnet.cmd. By default, Windows PE includes a Startnet.cmd script located at %SYSTEMROOT%\System32 of your customized Windows PE image. Startnet.cmd currently starts Wpeinit.exe. Wpeinit.exe specifically installs Plug and Play devices, processes Unattend.xml settings, and loads network resources
E:
Add Customizations with Unattend.xml
You can use an answer file with Windows PE to specify various settings and actions. When Windows PE starts, it implicitly looks for a file called Unattend.xml at the root of any bootable device (for example, a USB flash drive or a floppy disk). You can also specify an Unattend.xml file by using Startnet.cmd and Wpeinit.exe.
Note: The following procedure demonstrates how to add a customized script to a Windows PE image offline. Windows PE provides three methods for launching custom scripts: Winpeshl.ini, Startnet.cmd, and Unattend.xml. The Windows PE default interface is a Command Prompt window. However, you can create a customized Winpeshl.ini file to run your own shell application. You can also create your own version of Startnet.cmd to run a specific set of commands, batch files, or scripts. Unattend.xml is a new answer file format for Windows PE 2.0, which replaces Winbom.ini and Winpeoem.sif.
Reference: Include a Custom Script in a Windows PE Image