I use Ff
almost exclusively as my browser.
I've been using SiteAdvisor almost since its inception too.
While I use most of the Ff add-ons you note above, (except Adblock Plus Element Hiding Helper or the FireFTP),
I've never had any problems with SiteAdvisor since McAfee took it over.
It really helps me sort out the sites I want to avoid or warn others about.
SiteAdvisor installs no malware on your system.
The only easy day was yesterday.
...some do, some don't; some will, some won't (WR)