I'm not sure a free-willed being can be 'summoned', as such. If you could summon a mortal, most mortals would take a long time to get there, given traffic, since most mortals don't have the ability to teleport in.
Also, even if you could summon a mortal, and had his full name, it would only work for a little while before it lost its power, because of free will again.
An addendum to my quoted post: I'm not sure how that would play out with 'special cases'. For ex, Molly. We're not exactly sure what she is, currently. She's the Winter Lady, but is she also still human? If she's still human, what is the status of her free will?
I think you might could Summon Molly, free will or not, because in her case what you'd be Summoning would not be Molly so much as the Winter Lady Mantle, which carries Molly with it. Likewise, you
might in theory be able to summon Harry's mantle and have it carry Harry along.
But...I would also hazard that if Harry and Molly retain mortal free will, they might could fight your summons. If you do your summoning ritual just exactly right, Mab or Titania or the Mothers probably
have to come. But Molly I think it might be a contest of will, and even more with Harry, since his mantle is closer yet to mortal and made for mortals.