You seem a bit unclear with the Greek language.
Dodecaphonic comes from the Greek words Δώδεκα (dodeca = twelve) and φώνος (phonos = phone* as in phonetics, not as in telephone)
Dodecatonic comes from the Greek words Δώδεκα (as above) and τόνος (tonos = tone)
Dodecaphonic means something else, 12-tone composition.
Yes, but not necessarily. As you see above, I explained what it means exactly. When people refer to the 12-tone composition, they usually use words such as twelve-tone serialism, twelve-note composition, twelve-tone technique etc. You can take a look at Wikipedia to see some other names as well.
But the difference between the 12-tone serialism and the 12-note scale is that, the scale is an ascending (and then descending) collection of pitches, whereas serialism is not necessarily in an ascending (or descending) order.
So basically, if you want to call the 12 note equal tempered scale anything else besides chromatic, either of these words are linguistically correct. For most people though, the term chromatic scale would be the most commonly known.
But if you wanna go a different way, as in pentatonic, hexatonic etc, you can choose dodecatonic, so as to be consistent.
Not exactly thought in a scale per se, Nicolas Slonimsky in his book Thesaurus of Scales and Melodic Patterns, calls the division of the octave in twelve equal parts a Semitone Progression.
*a phone is any distinct speech sound or gesture, as per the Wikipedia article.