Why do you say "Flash Professional CC is not currently listed as a functioning program with Extension Manager CC"? Extension Manager CC does support Flash Profession CC. It seems that you installed Flash Profession CC but Extension Manager CC doesn't show it in product panel. Is it correct?
Swiffy is created by Google. It doesn't limit the maximum version of Flash Professional. As it is a mxp file and Extension Manager CC no longer supports mxp file, you have to convert it to ZXP file via Extension Manager CS6 (Standalone download is available at http://www.adobe.com/exchange/em_download/em6_download.html). Then you can install it to Flash Professional CC using Extension Manager CC.
Ahh there it is right under Tools>Convert .mxp to .zxp in Extention Manager CS6. Then switched over to EM CC, had to quit Flash CC but installed like-a-charm. Perhaps the Google Swiffy folks should just do this and offer this converted file as a download for Flash CC. Anyway Thank-You!
Worked great for me.
I converted the .mxp to .zxp but it cannot be installed. Adobe Extension Manager CC throws an error
"This extension cannot be installed. Flash Version 10 or higher is required."
installed Version is Flash Professional CC Build: 184.108.40.206
Adobe Extension Manager 6.0.8(.dmg)
Adobe Extension Manager CC 220.127.116.11
Flash CC 18.104.22.168 ( Intel Mac )
Got the same issue....
... restart the browser and the computer, it works, i see the extension, but when I am ready, and I will "export as html ... I recevied: "typeerror: Swiffy.compile is not a function"