First, rape is not just an act of violence.  It is a violation of free will. 

Secondly, from what Jim has shown us, the skinwalker is not the type to commit to a long term plot.  I don't think it would pretend to be a loving, caring mate for nine months just for one pay-off at the end.  It seems more likely to commit one act that would continue to torture the woman, making her fear what was growing inside her.

After giving birth she could do many different things (kill the baby, abandon it, etc...), but while still pregnant her options would be fewer.

Unless the creature's plan was to create an offspring.

That could indeed have been it's plan... Agreed that rape is a violation of free will, however posing as a lover or husband is also a form of rape..  As to long term plots, getting back at Morgan for killing one of them was a long term, plot.

(And back to Proven Guilty, under Illinois law, I'm pretty sure Harry would be guilty as an accomplice in murdering that warlock kid, but I do not have experience in Illinois accomplice liability laws).

    Or would that have been considered an execution lawfully carried out by another government, under the authority of it's governing body? 

If it were under orders/compulsion, then sure; it could have done whatever it needed to.  Then I move over to wondering who/what gave the orders, and why, and whether THAT is going to become part of the ongoing DF plotline(s)?

But if it weren't compelled... I return to thinking that any extended seduction would have been more time and effort than it would have found worth expending for ANY mortal.  I think a "simple" seduction, lost-weekend style, or overt rape, would be all the time & effort a naagloshi would be willing to expend on any mortal.

Except Mr Grey seemed to know his father, or at least what it was..  I think you are underestimating the amount of sadistic pleasure gained by the naagloshi...  It does have it's sadistic pleasures, that is why it spent so much time on poor Thomas...  The time and effort are worth it...

Initially Mab only saw Lea having both a strong Word-promised debt of Harry which would allow her to manipulate and control the young mortal wizard, and the Athame as too much power initially, so, she took Harry's debt because that would be a better long term use than the evil blade.  After all, Harry used impressive guile to outwit Lea while in Winter's domain specifically when she had all the power and courage to risk his own life in saving himself.  Mab probably watched the confrontation of Harry and Bianca, either in live form or some fae observing (she isn't bound from not using the information to harm Bianca because she is dead), and sees Harry's wrath and love driving him to make war.  Remember that Mab respects Love and the way it can drive people to do some very dark things.

I think Mab is well aware that Harry is starborn as well as a wizard,  she most likely impressed how he managed to clear her of the charges of murdering the Summer Knight, which also left her short a Winter Knight... So quite natural she'd want him on her team.... Let's not forget that though Mab may have taken on Harry's debt to Lea, she still could not force him to become her Knight.  As a mortal, Harry still has free will...

Just means he's watching Frozen, as a good Winterling should.

Try Princess Sophia..... 

Seduction comes in several sorts... there's the "fling" sort of thing, the one-night-stand, the lost weekend, the week-on-vacation-and-never-seen-again, etc.  That isn't really "in love," and the "big reveal" might be horrifying, disgusting, etc...  Inducing someone to fall deeply in love?  I agree that the sadism is far greater; but I doubt that a Naagloshi would care enough about any mortal, be patient enough, to invest all that time... they despise humans too much to invest that much into any of them!

Depends on what it's motives were....  What it did to Thomas for example, it didn't just beat him up to hold him to trap Harry... No, it sadistically did it over and over again to the point of death, so Thomas would have to feed until death over and over again, young innocent girls.. I call that sadistic...  So yeah,  depending on what it's orders were it is very capable of appearing as a handsome young man or worse yet murdering the husband or lover of the woman, taking his shape, get her pregnant, stick around as the loving lover or husband until she gives birth, then reveal the horror that it is... 

That was telepathy though, not a vocal conversation. Harry probably assigns attitudes of vague superiority as sounding British largely thanks to his experience with Langtry.

  How do we know that isn't how he is communicating with the "British" prisoner?   I also doubt that the original Merlin would use British slang like, "piss off.."

We next hear of Lea in Dead Beat.  When Harry summons Lea , Mab appears wearing a knife that is assumed to be the Atheme.  She tells Harry that Lea is detained but in no danger.

True, but what we don't know is how Mab acquired the Atheme..  We know that Lea is detained, but don't know if it is because she defied Mab or because she is showing symptoms of infection or both.. As of Summer Knight Maeve appears more or less sane if one can go by the scene in Mac's bar...  However at some point she came in contact with the Atheme, became infected to the point where Mab couldn't cure her as she had Lea or herself..  So was Mab's contact with the infected Atheme brief?  We next hear of Lea in Dead Beat.  When Harry summons Lea , Mab appears wearing a knife that is assumed to be the Atheme.  She tells Harry that Lea is detained but in no danger.

So one assumes that Mab got the Atheme from Lea... But in Cold Days after Maeve's death Mab says.  page 503 hardcover

"It was the knife," Mab said.
"Knife?"
"Morgana's athame," Mab said in a neutral tone---but her eyes were far away." The one given by the Red Court at Bianca's masquerade.  That is how the Leanansidhe was tainted---and your godmother spread it to Maeve before I could set it right."

Which begs the question as to how the infection is spread in the first place...  Because either Lea gave the knife to Maeve and Mab took it from her before Dead Beat, or it can be spread through other means which Mab was unaware of before it had gone too far in Maeve...