I did tested first two extensions that you posted, in Opera stable standalone (usb) 58.0.3135.53
I had some problems at the beginning...
when I installed them, I couldn't see any of them on my extensions page and Opera kinda frozen...couldn't load any page
but after restart everything worked
I see previews on google search and notepad works (as far as I can tell)
btw. Opera is preventing extensions from injecting stuff on search results
you need to enable it first on opera://extensions