Board Thread:Speculation House/@comment-27144409-20160720154947/@comment-25936766-20160802212636

Sentry 616 wrote: This may have been planned as Cinder's special power source. I thought her "Power source" was originally (just) Dust Clothes?

As for the idea itself, my headcanon is that possibilities 1 and 2 that you mention in the OP are how Dust Infusions are done.