FFMPEG uninstall/remove or change path possible ?

Having a little trouble getting a custom made web app to run, every feature works except the interactions with ffmpeg for thumbnail generation.

Dev said it has to do with the path where the binaries are and the configuration.
He initially developed on ubuntu and says it should be running from /usr/local/bin not from the standard /opt/bin/ffmpeg bin that comes automatically through menu item 19

Is there any way to completely erase all traces of ffmpeg and its configs/aliases/links whatever ?

---

 

thank you <3