For details of how to uninstall add-ons see https://support.mozilla.com/kb/Uninstalling+add-ons

Windows Shopper has been added to some add-ons, for example IE Tab Plus. If you have IE Tab Plus, open the IE Tab Plusoptions for a setting to turn off Windows Shopper. Alternatively uninstall IE Tab Plus and install IE Tab 2 instead - https://addons.mozilla.org/firefox/addon/ie-tab-2-ff-36

Superfish is probably embedded in an addon, but there is no telling which one. I disabled IE View lite - but still have Superfish. It is not listed either independently or under any of my addon options.

There SHOULD be a way for Firefox to report where it is hidden and how to disable it without having to disable and re-enable all addons one at a time.

The add-on Converter 1.0.0 also uses Superfish. The relevant option to disable is "Superfish price comparison" in the Generic tab.

Awesome Screenshot also embeds Superfish and doesn't document how to turn it off, only that it can be. Just right click anywhere on a page and a menu will pop up with Awesome Screenshot somewhere in the list (mine was at the very bottom). Go to AS > Options and uncheck the "Enable similar product search powered by Superfish" option, then restart your browser. This should take care of it.