Determining which contacts use Facetime
To get around this I have added the letters FT to a contacts last name eg "Surname FT"  then all I need to do is search for  "FT" and there I have a list in alphabetical order of all contacts I can FaceTime!

So, create a new message, add all contacts, take note of which ones are blue, and add FT to the end of their surname eg. "Surname FT".  Now when you want to FaceTime someone Type FT into the search bar and presto! You have your list. Hope this is helpful, enjoy :-)