I've been trying to do something similar to set up Windows VMs with developer tools. This would be awesome if there was a way to inject a `ps1` script where we could go through the awkwardness of installing choco and various dev tools.

For anyone interested, the magic incantation in the autoattend.xml is:

    <settings pass="specialize">
    <component name="Microsoft-Windows-Deployment" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS">
        <RunSynchronous>
        <RunSynchronousCommand wcm:action="add">
            <Order>1</Order>
            <Path>cmd /c powershell.exe -ExecutionPolicy Bypass -File A:\scripts\setup-dev.ps1 &gt; \\.\COM1</Path>
            <Description>Run dev setup script</Description>
        </RunSynchronousCommand>
        </RunSynchronous>
    </component>
    </settings>

Even better would be figuring out how to slipstream the choco packages into the ISO - it's not super reliable to install these packages in my recent experience.

https://boxstarter.org has been working on this for a long time and might have some useful ideas.