can I get the XFINITY/COMCAST app with the Amazon Fire Wireless TV Stick ?
You need an approved Roku streaming device or TV, or one of the listed Samsung or LG Smart TV models. See https://www.xfinity.com/support/articles/xfinity-stream-beta-app-faqs#all_devices.
COMCAST (if one thinks they know what customer service means) says yes, but some say no. It sounds like an Amazon Fire Stick is NOT the way to go.