As far as the over/under on when the remains will be ruled out or identified as the Jamisons, I'm going with 3 months and will reference the Charles Crowder case-his remains were sent to Texas for DNA analysis and 3 months later they had a match, also LE had suspected that the remains where Crowder's.
Since the remains found (at least the skulls) had no evident trauma, this leads me to think, if they were murdered: they were strangled, stabbed or had throats slashed. Its unlikely anyone is going to kidnap an entire family using a knife. So lets say a gun was used to get these 3 to the location they were to be murdered. (whether on foot or vehicle). This also suggest a scenario that requires 2 people and what motive would 2 people have to murder an entire family especially if they ran into each other by chance. If by chance what are the chances the murders had the means to murder a family without the primary weapon being a gun. That person(s) would've had to have brought a knife, a gun and a rope and the chances of 1 person carrying around all 3 is unlikely. Once that person(s) got them to the location they were murdered and didn't shoot the 1st one and instead strangled or used a knife to murder them (if only 1 purp) if the other 2 were not in some way bound up there would be an immediate attempt to fight or flight as well as some screaming. The chances of 1 murder being able to overcome all these obstacles seems unlikely.
LE describe's the area of the remains as difficult to access and obviously in close proximity-which says to me that (1) there where 2 purps, and to me, thats unlikely if it ends up being the Jamisons, NOT if its 3 other people involved with drugs-deal gone bad (2) these people are not related and murdered separately- probably strangled (like serial killer/rapist/kidnapper) and bodies dumped later, or (3) people who decided to take there drugs (maybe meth) into the woods, get high and died due to OD or even bad batch of drugs.