What is the narrative impact of having supernatural abilities externalized into a companion?
If having a companion with a power means that the player character has the direct narrative benefit of that power, then the companion is a special effect, and any narrative limitation is best handled by Compelling an Aspect.
I wonder if a GM will have to adjudicate this on a case-by-case basis. Three creatures may have the Wings ability, with vastly differing impacts on the plot and/or the player's agency.
Bird with Wings, Echoes of the Beast and Diminutive Size: ostensibly a 3-Refresh suite of powers, but they will rarely directly benefit from those powers. Player can't fly. Player can't fit into small spaces. At best, they can get a headsup from the bird on something out of the ordinary using its senses. The player may get some information they couldn't ordinarily get. The player could buy this as a Supernatural Sense for 1 Refresh instead, but doing so would mean that they don't have another pawn on the board able to make Maneuvers or Assessments. 1-2 Refresh, depending on the table.
Giant hawk with Wings, Echoes of the Beast, and Claws. 4 Refresh. But oh what a Refresh that is. Player can still get a headsup from the bird on something out of the ordinary using its senses, and other information they couldn't ordinarily get. Player still can't fly, of course, unless the Player and GM agrees that a roughly man-sized Hawk can use its Might score to carry a passenger. But either way, this is more than just another source of information: this is another effective combatant on the board, making Maneuvers, Assessments and credible Attacks. A combatant with a very useful (but not universally effective) maneuverability. 2-4 Refresh.
A mythical Roc, with Hulking Size, Wings and Echoes of the Beast. 4 Refresh, unless you buy Claws. Maybe not *as* useful a combatant, but it has Intimidation potential, and you can easily justify letting people ride it and gain at least communal use of the Wings power. It could still provide the player with information he couldn't gain on his own, and it can serve as a movement vector. And it can certainly have battlefield impact through Maneuvers and Assessments. Also 2-4 Refresh?