Very good questions all! There may not have been two knives and in fact my THEORY is that there was one knife, likely a stout and very sharp dagger. I'm not inclined to believe it was a clasp knife unless it locked like some today do because with no hilt the killer would likely have injured himself. I rule out a bayonet because their length makes them unwieldy if not on the front of a rifle.
I'm not surprised that there were no signs of sexual intercourse. It is possible that her last customer did not penetrate and instead she placed him literally between her legs rather than in her vagina.
In spite of Television and movies showing strangling as easy, it is not. It is possible that she was still alive though comatose when the killer started stabbing her.
There were 39 stab wounds She would have leaked like a sieve. Given the proximity of the abdominal wounds to the vagina that would account for the blood and if the vaginal area was not actually wounded, the coroner would not mention it.
All in all you pose some intriguing questions. Thank you for the post it was entertaining and illuminating.
Neil "Those who forget History are doomed to repeat it." - Santayana