These indicators are missleading since the samples are automatically tested which doesn't yet support dependencies with other required libraries (e.g. Adafruit_GFX).
So the indicators are right and wrong.
The samples don't build without the 3rd party libs but would when used right.
Your bunch of link errors suggests that there are multiple copies of the Adafruit_GFX lib in your project.
That happens when a lib brings its own copy of a 3rd party lib (=bad habit).
So just remove the Adafruit_GFX library again.
Then follow the steps here (that's from the thread you linked)
And try again - please post the resulting error messages (if any).
I'll have a look at that sample soon and come back to you.