"Hentai" was a completely peripheral issue. It came up during Neal Westerfield's testimony. The forensic entomologists on the other hand were called by both sides to attempt to establish the time of the victim's death, either in support of, or to contradict, Westerfield's alibi.
So, again: What is the connection between the "hentai" and the entomological evidence?
Here's how I figure it: the kidnapping itself and possibly rape was done by David W. Another rape, the actual murder was committed and the body dumped by Neal W. That would explain WHY the bug evidence said she was killed and dumped while David was under police surveillance.
No. There was no "hentai" on the computers' hard drives, nor on the loose media at the Westerfield residence. Neal testified, and his testimony was corroborated by the computer expert, that he had viewed "hentai" with his web browser. The video to which you refer was not "hentai." It was live action, from David Westerfield's collection.
As I said previously no evidence was presented that Westerfied the elder was interested in "hentai." He was way beyond the cartoons which you seem to insist played such a large part in this case. Why are you so obsessed with your "hentai" angle?
Oh, OK, Rufus, since you asked I don't know. I don't watch hentai.
However I know someone who could tell you all you want to know and probably more. PM me (edited for ad hominem content)
If you don't know what their favorite hentai was, then how do you know they were acting it out? It's sounds like you are just making stuff up as you go along.