Reference image built under administrator, copy profile done via sysprep, all other browser the settings (aka homepage) stuck, except Google chrome, the copy profile doesn't seem to carry over settings for chrome.

Is there another way I could set the homepage for all users including new ones? using a script?

Any advice would be great.

By default, Google Chrome installs for the current user only. Did you use the alternate installer when creating your reference image?

It will depend on where Chrome is storing the data. The installation itself (if using the web installer) goes into the user's %AppData% folder, but not everything stored here will migrate to a new profile even with CopyProfile set. I don't know specifically where the homepage data is stored for Chrome, but it would be interesting to see a before and after to verify it's not backed up.