Yes. I have it set to true and my Firefox does not make any connection to Firefox Sync.
Yes but this only gets some NoScript settings. In my profile, looks like it's:
- Permissions and preset configurations,
- XSS user choices,
- Cross-tab identity leak protection global settings,
- The "Enable setting permanent permissions in incognito/private tabs" setting,
- The "Any capability blocked in the top document must be blocked in its subdocuments too" setting.
Which IIUC should be enough for what you're seeking?