Hi @willy,
On further review, there is this little diddy to deal with:
I expect this needs a different library that interleaves the serial switching to talk to the ESP and keep the debug port free.
It may be as easy as grabbying the uno wifi library and replacing the espwifi reference with UnoWiFiDevEd.h.
From the learning tab at Arduino - Home
If you are using the Arduino IDE 1.7.x then continue to use the ArduinoWiFi.h library.
Instead if you are using the Arduino IDE 1.8.x then download the UNOWiFiDev.Edition library from Library Manager and modify the code, replacing #include <ArduinoWiFi.h> with #include <UnoWiFiDevEd.h>
Cheers,
Craig