I agree with everything you say. There are some reports from various media sources that I have checked against what LE said, and those reports really were supposed to just reprise what was said at the press conference, and they have flat out incorrect info in them that can't be cross checked anywhere. Also, absolutely LE is not telling us everyhing or even most of what they know, hopefully, just a tiny bit of what they have. The AM case actually had an official news block on it because the evidence had to be presented well, with absence of body, the DA needed everything he could get to secure a conviction. Defense, through discovery does get a look at what the state has, but there is no need to taint to jury pool, not need to put ideas in others' head. Note that JM's attorney hasn't made a statement, not one. Not a peep from that quarter. My guess is that they are sitting very tight, hoping Hannah's body is not found, because frankly, without a body , in most such cases, a conviction isn't going to happen. The AM case is unusual and had a lot of very explicity DNA evidence on top of a perp who talked and couldn't tell a lie that would hold up and had to back track with so many storieds that no one could reasonab'y believe a word he said.
We really don't know what tied the case to the car even before JM was brought into the picture. Maybe LE did try to talk to him. If the info is as we know it, I think it was a huge gaffe on part of LE to go serve the warrent on the car without a very skilled interviewer with them to baby sit, commiserate with and try to get any info out of JM instead of setting him off as that whole thing did. LE directly said that they don't even know when and how he and his roommates left. No one there with coffee and donuts and a sympathetic ear on the scene, carefully watching JM's reactions, interaction. That, too me is a major fail, but then maybe there was and LE isn't telling. What they found there, why they could get that warrent is not known to us.
We do know that even with what was found, even that next day at the station, LE couldn't nab JM. Still not enought to charge him. It took the reckless driving for them to do that and that they went all out on such a trivial charge, to me, signals that they really did not have much in the way of evidence.
From looking at all that has transpired and how JM has reacted, I too, am in the camp that thinks he was guilty and that with a link to the MH murder, LE may well have caught a serial rapist and kller. But the MH case where there may be definitive DNA, and certainly that 2005 rape case, is where LE may have the best evidence. When I lay out distinct possibiities for Hannah, unless LE has some really good stuff in evidence, I don't see how it comes close to the guilty without reasonable doubt with a presumption of innocense to be observed which is our standard that has to be observed in court. Heck, yes, it's possible Hannah is still alive. Even Longo said so a couple of days ago, remember? Many of don't go for the slavery ring theory, and I'm one of them who doesn't think it's likely at all, but hey, it is possible. There are people who believe this and in absence of a body, well, yes, it's posssible JM turned her over to someone who might have been so involved. Hannah could have met up with someone and disappeared to the tropics, was off to meet the person, got lost, and JM gave her a ride somewhere to someone and the poor dumb JM is now stuck with a stupid story and no proof in a climate where everyone wants his head on a stick. I don't go for any of this but with what we know, yes, possible.