Yes, EK could, because he never carved off that mortal choice, same as Odin I believe.(which Woj would more or less confirm) There are 4 mortal choices floating around Fairie. And specifically, the queens and ladies are only a part of the Mothers power, we know they spun off all the lesser mantles, including then, giving the Queen the ability to make the Knight. The '3 queens' don't contribute, The two graces in opposition(tell me creator and destroyer are not archangel material, if not more) are broke down to maintain balance between the two with plenty of insulation filler in between. So Knights are indeed a created thing, from a mantle, from a grace...
Although it seems to play into the whole fallen shadow/ earthly mirror thing as part of the reason Knight's exist too.