I've thought about that failed attempt and many times and remain torn. There was a delay in the reporting the incident and if I'm not mistaken, the description of the vehicle didn't match the description of Kam's truck.
I believe that it was them and witness accounts aren't always correct but I'm not sure the public would have benefitted from being told to watch for an entirely wrong vehicle. Perhaps that report actually delayed tying the two murders together.
I'm not saying anything about the public being told to be on the lookout. What I'm saying is:
a) If the police had mentioned the July 17th murder attempt during the August 7th press conference, that would have ended a lot of the speculation about motive, premeditation, etc. and therefore a lot of the public attention to this case. Since there wasn't going to be a trial, there was no reason not to mention it at that point.
b) The police had this witness account on July 21st indicating Kam and Bryer may have been involved in the murders rather than victims. Yes, the car description was inaccurate, but that is very common for witness accounts, especially in a high stress situation, especially at night. Yet they weren't named suspects until late on the 22nd by which time they had already burned the car and gone into the woods. Between the time when this witness report was made and the time when they were named suspects, they were stopped by the police, but let go because they weren't listed as either missing or suspects in the database at the time. This entire manhunt could have been avoided and it's possible they could even have been captured alive on the 22nd.
The families of victims receive information only when it's been proven fact
Yes and my point is the police had definitive evidence tying them to all three murders as well as a fourth attempted murder by July 24th.
There's also significant evidence to indicate that the other members of the suspects' families didn't get information either. For example Bryer's great-uncle said on August 9th that they hadn't gotten any more information than what was in the media. The leaking of the information about the videos -- twice, first that the goodbye video existed, and then that there were multiple videos -- must have been done by some of the suspects' family members (and not Bryer's dad because he didn't even know about the goodbye video until after its existence was leaked to the media, and by the time the multiple videos detail leaked, he was under an NDA). The logical reason for that would be to put pressure on the police. (Plus there's other information I've come across suggesting that other family members didn't get any more information than the public did, but it's not substantiated enough to elaborate on here.)
I don't believe they intended to ever release the videos to the public nor do I believe they should, out of respect for the victims and their families but I do believe that it was evidence that tied up loose ends and they were obligated to present their findings.
I don't believe the police would have ever disclosed the existence of the videos had the information about them not been leaked. There was no reason to -- they had enough evidence to say Kam and Bryer did it either way and the videos didn't provide any information as to motive. And the only reason why the information about the videos leaked to the media was because of the secrecy.
Without a murder weapon (at the time) they didn't have enough to charge them with Lucas and Chynna's murder.
Except they did. It says right there in the report: "On July 24, 2019, the firearms lab provided preliminary findings to the investigators. There were two firearms used in the Fort Nelson homicide, both of 7.62 x 39 mm calibre. One of the guns used in Fort Nelson was used in the Dease Lake homicide."
They already had enough to charge them with Professor Dyck's murder by July 23rd. So by the transitive property of murder weapons, it would logically follow that they could also have charged them with Lucas and Chynna's murders by July 24th. And could have told the public at least by August 7th (since they knew there wouldn't be a trial by then) that the same weapons were used. Both of which would have completely ended the significant amount of speculation and conspiracy theories on whether they really did it, and a lot of the media attention with it.
tl;dr The police created most of the publicity and notoriety of this case.