There are just so many things about JL's story that seem so out there and unlikely to me, but there are parts of it that fit with known facts and rumor, too. I want to just discredit the guy outright because Craigslist Hitman Ad isn't the most likely of scenarios, but a lot of it kinda fits with what we know. Then again, if we know the details fit, he very well could too. He was only picked up the night before last and has internet access. He was probably reading about the case, especially since no one but LE was looking at him. Anything that we know he could have known to come up with his story, right?
For example, at first I thought, re: the gun, that JL saying it was brought by NB could be a sign that he was telling the truth because it wasn't officially confirmed yet that NB's boyfriend's gun was gone and that NB's boyfriend called her in missing. So how would JL know to come up with that part of the story? Well, I'd seen it talked about in rumor on social media before confirmation, and if I saw it, he could have too. There are a number of rumors I've seen that have been proven to be true, i.e. her COD, so those are details he definitely could have picked up to prepare his story with.