Yea AlfaRomeoCares is utterly useless. Check out my thread on them not doing anything about their shitty dealers botching a repair job.
Anyways...I too have the same issue as you did...hard to start after fill up, and got a "P0456 evap small leak detected" code. Did you ever find the Mopar part number for the purge valve? I can't seem to find it anywhere. Also, the part diagram somebody posted shows the valve...it looks totally different than the one in your pic...am I missing something?