Sysprep AutoLogon \Edit file to windows guest VM

I have 2 questions pertaining to Windows Guest VM's

I am using the:

Customize Windows with single NIC and credential

workflow to customize a windows VM I am deploying from template. I need to specify the account for the autologon option but cannot figure it out. Is there anyway I can specify the account and domain I would like to autologon with?

Also, is there anyway I can specify a custom sysprep.xml file OR customize attributes not specified in the workflow but available in the sysprep/unattend.xml spec?

Lastly, I need to create a file in the VM being deployed to pass some parameters for some custom software installs that are done as part of the sysprep process. I found the

guest script manager package

and was able to successfully create a blank file in the vm but I cannot figure out how to edit the file and write some data to it. When I try to edit the file I get access denied error even though its the same account used to successfully create the blank file. Is there anyway to create the file with data or edit it after the fact to add the data?

Thanks.