
Axl |
I agree with Are's interpretation, although the feature could have been better worded. It is odd that the feature explicitly seems to emulate a spell, yet is supernatural, not spell-like.
I suspect that if the feature as a whole included just the flight, it would been made spell-like.
Mantle of Moonlight is another funny one. It makes sense that the first part of the feature is supernatural. However forcing people into a rage, "as per the spell", probably should be spell-like.

Axl |
Per the Fly spell, you would have to use a standard action to start the Lure of the Heavens flight. As the duration can be extended after each minute, I would allow the oracle to choose to extend the duration at the end of each minute as a free action.
With your houserule, you are effectively allowing the oracle to cast Fly as a "free" action - arguably better than a quickened spell. If I was the GM, I wouldn't allow it.
The meta-question is: would it be overpowered to give Fly a casting time of a swift action (i.e. like a quickened spell)? Perhaps not, but that doesn't mean that there should be a houserule to change the spell in that way.