Mainly, I'm refuting the idea that Elaine's Nemfected-or-Not status is something a soulgaze (or any other magical inspection really) is likely to detect.

I don't think the "pain" mattered to her in the slightest:  she "wasn't happy" because "happy" is the kind of the antithesis of Mother Winter's personality.

My point here is that even with Toot -- one of the very-weakest of all the entities he "summons" -- Harry isn't "summoning" him, in the sense of "making him" come.

Harry is luring them, one and all; attracting their attention & giving a sense of something they want, something they're interested in.

It was Dead Beat, not PG; but yes, we presume Lea was a sidhecicle at the time.

The point, however, is that Harry summoned the Leanansidhe and got Queen Mab instead.

So the "rules of summoning" are (to cross some streams) really more what you'd call "guidelines" than actual rules; welcome to the writings of Jim Butcher (who delights in misleading the fans).

"Disturb me?  Hardly.  I am here only to fulfill the duties I have been obliged to take upon myself.  It is no fault of thine that this summons reached my ears.
I straightened up slowly and avoided her eyes.  "I had expected my godmother to come."
Mab smiled.  Her teeth were small white and perfect, her canines delicately sharp.  "Alas.  The Leanansidhe is tied up at the moment."

"She is bound," Mab said.  "She is in some discomfort.  But she is in no danger.  Once she acknowledges who rules Winter, she will be restored to her station.  I can ill afford the loss of so potent a vassal."

I think the lure vs. summon depends on the power level and relationship of the two involved. Mother winter had to respond to Harry because his request was legitimate, but he could (obviously) not have forced her to show up except though obligations between Mother Winter and Winter Knight. But with a being closer to his own power level (like the Erlking apparently) he can force the being to show up if he knows the right names, ritual ingredients etc.

Remember when he "summoned" Lea... and got Mab.

Remember when he "summoned" Uriel (as if).

Remember the early books, where he "summoned" Toot ... which was, very explicitly, a lure-and-trap (despite how very weak a faerie Toot is).

Harry has power to affect Mother Winter, he summoned her, Titania and Mab(willing summons) in Cold Days. What he does not have is the power to compel them to obey him.

I think a deal can be done or has been done before just not in the way the politicians thought it was. In my mind, i can see Lara, Mab or what ever entity proming a young politician money and support in exchange for a few favours. Dude agrees thinking its a normal thing, usual political deal and what not, only for the entity to came back and collect only then for the guy to realise f..... it wasn't a human but who you gonna tell
Ps the White court or rather house wraith most likely has the most political connection. I mean political and non political sex scandals are an everyday occurrence.
On that note politicians have side pieces is not rare its the norm. On of the wraith sisters encounters a promising politician gets him /her addicted and boom

"Not having it could have gotten me killed, too," I said.  "And then you'd have wasted all that time you've put in trying to recruit me to be the next Winter Knight."

"Nonsense," Mab said.  "If you died, I would simply recruit your brother.  He would be well motivated to seek revenge upon your killers."

That's a direct statement on Mab's part.  Not an implication, or a suggestion, or a hint, it's a direct declarative statement.  Either she means it...or she uttered a falsehood, which as far as know she simply can't.

Quote
  "He isn't mortal," I said quietly. "I thought Knights had to be mortals,""He is in love," Grimalkin mrowled for Mab.  "That makes him mortal enough for me." She tilted her head.  Though I suppose I might make him an offer, while you yet live.  He would give much to hold his love again, would he not?"

RCV's are entirely inhuman.

They "wear a flesh mask" but it's an ectoplasmic summoning; the real creature is a rubbery batlike thing.  They only act with self-control for their own advantage (incliding self-preservation, e.g. in the face of a superior foe).

WCV's are humans; they are humans harboring "hunger demons," but they are still human, and we know this with certainty:  wizards can soulgaze WCV's (but cannot soulgaze RCV's).

Most White Court vampires are the offspring of a WCV and a mortal.  Half mortal is the norm for them.

She said she would.  Harry asked her what she would do if he had been killed, since he knew she wanted him as her knight.  She said point blank in response that she would offer it to Thomas.  Not that she would consider it or maybe, but that she would offer it to Thomas.  Straight declarative statement, and Mab always speaks the truth.

"He isn't mortal," I said quietly. "I thought Knights had to be mortals,""He is in love," Grimalkin mrowled for Mab.  "That makes him mortal enough for me." She tilted her head.  Though I suppose I might make him an offer, while you yet live.  He would give much to hold his love again, would he not?"

She can use magic.  You don't have to have free will to use magic, but having free will is what causes magical techbane.  That's why Fae can use magic and also use smartphones and other electronics, no techbane.  But the combination of magic and free will screws up electronics and other technology

One of Harry's worries, in fact, is that if the general public ever realized just how compromised every institution and group is by the supernatural, society would break down.  That was part of how Mavra was able to blackmail him back in the day.