Hi Megan -
Thanks for the response, that's what I was worried about.
Reading the Packer docs, it sounded like the user data provided to the packer "user_data_file" attribute shouldn't persist, but it seems like that goes out the window when Windows and Sysprep are thrown into the mix.
I looked at clearing the user data as part of my provisioning using AWS for Powershell command Edit-EC2InstanceAttribute, but it appears that only works on a stopped instance.
So unfortunately, it sounds like if you use "user_data_file" for initial WinRM configuration in Packer, you're out of luck if you want to use user data for child instances created from the custom AMI.
Don't want to increase the scope of the question too much, but is there a better way to initiate WinRM connection than using "user_data_file"? As I mentioned, that seemed to be the only way I could get WinRM up and running and was recommended in most of the docs I found.