is macfest 4.0 needed on my safari extensions?

No. I don't have it on mine.

Back up all data before making any changes.

You installed a variant of the "VidX" trojan. To remove it, first open the Applications folder by selecting

Go ▹ Applications

from the Finder menu bar, or by pressing the key combination shift-command-A. Look for an item named "VidX," "MacVx," "MacFest," "MacMin," or similar. If present, drag it to the Trash and empty. If in doubt, order the folder window by date modified and delete any application near the top that you don't recognize.

From the Safari menu bar, select

Safari ▹ Preferences... ▹ Extensions

Uninstall any extension you don't know you need. If in doubt, remove all of them. None is needed for normal operation. You may have more than one that's malicious. Do the equivalent in the Chrome and Firefox browsers, if you use either of those.

"Searchme" is malicious, as is anything else with the word "Spigot" in the description. The other one I don't know about. If you don't know what it is, remove it.