Consider switching to ungoogled-chromium as a base
Recent news:
Considering the continuous invasive "privacy respecting" of Mozilla corporation and its ties with Google and other companies, it is time to consider moving away from Firefox and switching to a truly privacy respecting one.
Unlike Firefox ungoogled-chromium makes ZERO background and ZERO unsolicited connections. It is also very easy to set up a tor proxy and use it with ungoogled-chromium. The only thing it lacks is the reset-identity functionality and the use of separate Tor circuits/IPs for different sites.