I think @zogstrip suggested entering the forum database you want to replicate (via SSH), clone the site_settings table into that database and replace that particular table in each new site you’re going to create.
One caveat: It uploads only settings that are marked as changed. This means that if there’s some setting that’s changed on the site you’ve uploaded that you want to restore to default with the script it won’t work. The solution is to edit the JSON file so that the default value there doesn’t match the value you want to set.
Now what’s needed is a way to easily download all themes and then upload them. Uploading
a set of files shouldn’t be hard to do. Downloading themes by hand could be tedious, so some automated way to get all of them would be nice.
As long as the setting is available it will be set. Settings that don’t exists can’t get set, but make only that it doesn’t get set. For example, if you have a plugin installed on the system your are copying from its settings exist only if the target system has the plugin as well. When that happens an error is presented for each unavailable setting.