Omnibus.safariextz removal (Threat: OSX - DR. Antivirus) suggestions pls.

Uninstall Dr AntiVirus as per the developers instructions. No Anti-Virus software or so-called “cleaning” apps are needed or recommended for Mac OS. They can conflict with Mac's own built-in security. At best they will slow your Mac by using unnecessary resources and at worst will bork your entire system.

Get rid of (uninstall) that useless piece of software.

Do you have Omnibar extension installed?

See if you can find the file(s) using one of these programs. If you go Finder/View/Show Path Bar, it will show you where it is located.

EasyFind – Spotlight Replacement

Find Any File