You can create profiles in firefox with firefox -CreateProfile someProfile and open them with firefox -P someProfile. You can have 1password pre-installed, and the usual new profile things turned off by setting C:\Program Files\Mozilla Firefox\distribution\policies.json to:

{
  "policies": {
    "ExtensionSettings": {
      "{d634138d-c276-4fc8-924b-40a0ea21d284}": {
        "installation_mode": "normal_installed",
        "install_url": "https://addons.mozilla.org/firefox/downloads/latest/1password-x-password-manager/latest.xpi"
      }
    },
    "UserMessaging": {
      "SkipOnboarding": true
    },
    "OverrideFirstRunPage": "",
    "DontCheckDefaultBrowser": true
  }
}