Hello, I'm new here, but I just caught up on this interesting theory. I have a couple of points I'd like to add, although I know this is a older thread.
"What makes you think he had 3 hotel rooms? They say he only had 2 rooms."
I can answer this one. There are three hotel rooms in the movie: 2 rented by Lenny, 1 was being rented by Dodd. I think the point here is how comfortable Lenny felt inside Dodd's room after Lenny forgot where he was and took a shower.
(by the way: Leonard gets out of the car the other side he got into)
I looked into this and determined it must have been an editing mistake in the movie. When you read the script it makes it clear that Lenny got into the passenger side seat. "Teddy shrugs. Leonard motions Dodd into the driver’s seat, then slides into the passenger side. They pull out of the parking lot, Teddy following in his GREY SEDAN."
However, you do make a good point about how the story of John G doesn't make sense. Although, you make some leaps to unreasonable conclusions without any solid explanations. To me, this is more evidence of manipulation, either by Teddy or more self manipulation by Lenny. How does Lenny know the cops didn't look for the second assailant? He can only know what his notes and files tell him, and we already know that the file has been tampered with (pages missing, lines crossed out).
The other points you make about Dodd not realizing Lenny was in his apartment are also interesting, however I do not have an alternative explanation for that.
One of the murders being of a gay priest who is raping Leonard in the mental ward? There is absolutely nothing from the website short story or film that begins to present that in any way, and it makes you seem as sick as Leonard.
Warden doesn't necessarily mean priest, in this context it would mean his caretaker in the mental institution. And besides the line Erwin previously provided in another thread from the movie ("If I could just reach out and touch her side of the bed I could know that it was cold, but I can’t."), I've also found a supporting quote in Memento Mori: "He reaches out for the alarm clock, but he can't move his arm." It is very odd Lenny from the movie and Earl from the story both have lines in which they claim to be unable to move. In the story, Earl is getting a tattoo, but people are not usually strapped in when they get tattoos, so why can't he move his arm? I agree though, it is a huge leap to say this implies he was raped.
In addition, I've taken a look at what Erwin calls the openingshot. It is interesting that there is a question mark and the word deleted, but I can't reach the same conclusion that this represents five friends as I can't find any evidence to support that. As that is where Lenny places the Natalie photo, it seems that Lenny had that spot prepared awaiting that photo. The area where the Teddy photo goes does not have similar box, although I did spot another editing error here. When Lenny is about to place the Teddy photo, you can clearly see that the Natalie photo has disappeared off of the wall.
My conclusion is that Natalie is special and has a more significant role then shown in the film. In movies or tv shows, when cops are creating a map of the power structure for a gang, for example, they place the gang bangers pictures on a wall and draw lines linking the members together. If there is an unknown person, like a boss, they usually draw a box with a question mark where that person would fit in the power hierarchy. You can see how this line of thought leads me to conclude Natalie is important in someway.
Overall, I prefer the more literal explanations and it seems clear to me that Lenny was responsible for the attack on his wife. There is evidence of this in both the movie and story. I'm currently unclear on all the details, but here is my theory: Lenny hired someone to kill his wife (possibly an unknown junkie, or someone connected to the movie). Unknown to Lenny, the junkie brought a partner (John G). Lenny's plan was take the hitman by surprise while he was busy attacking the wife, then finish his wife off himself. In this way, Lenny can collect the insurance money while looking like a hero. He takes his gun and shoots the assailant in the head. He then climbs on top of his wife's body and starts strangling her himself. Before he can finish off his wife, John G comes up from behind and smashes Lenny's head in.
Evidence of this is shown in the memory/flashback Lenny has while choking Jimmy, a scene is shown from the attackers perspective. When the scene showing the assault is revealed, Lenny is seen getting on top of his wife in the same position as the attacker from the strangulation memory. Also, there is a bit from the story in which Earl is giving himself a tattoo that reads: "I RAPED AND KILLED YOUR WIFE." Earl is giving himself this tattoo, so the "I" refers to himself.
I claim Lenny wanted the insurance money because it fits and that is a motive straight out of the film noir genre. When asked by Teddy where Lenny got his nice suit and car, Lenny quickly and confidently replied: "I used to work in Insurance, we were well covered."
Following this line of thought, Lenny initially wanted to kill John G, not because he raped his wife, but because he had to eliminate all loose ends so that the assault is never traced back to him. Eventually though, he may have twisted his memories into thinking it was for revenge. Just as Lenny shifted the blame for the overdose onto Sammy Jenkins, he shifted the blame for the assault onto John G. He does this around the same time he convinces himself she died during the attack, so he feels like he is chasing a murderer who outsmarted the law and escaped justice.
Phew, I know I've typed a lot here, and maybe this should have been made a new topic, but this is a good as place as any. I just watched this movie a couple of weeks ago, and it's been stuck on my mind ever since.TLDR:
Erwin Fortuin makes some interesting points, but ultimately I feel the best explanation is that Lenny hired a junkie to rape and kill his wife in an attempt to collect the insurance money.