I keep thinking this trip is being organised in a really bad way for multiple reasons.

• Relying on donations instead of funding it yourself is very open to abuse. How many times have I seen people begging for donations but never delivering?
• I doubt the people involved have been properly vetted beforehand. I can imagine all kinds of fuckups caused by the group having people who are either too unfit, unprepared, socially unsuitable, or have conflicting opinions on how the search should be carried out. A trip like this needs a single leader who dictates the course.
• I have serious doubts about whether it is safe to do this trip with total strangers. High profile (suspected) murder cases like this often attract "copycat" muderers. Personally, I would never go beyond the Mirador with random people I met on the internet given the surrounding context of the case. The only way I could imagine doing a trip like this is would be with a group of people I already knew and trusted.
• The trip is being widely publicised which is only going to attract attention towards it when you get there. If I had the intention of searching the area, I would want to keep it as low key as possible to reduce the chance of any interference from the locals. If there really are hostile 3rd parties in that area, the last thing you want to do is advertise you are coming.

Perhaps you have considered all of these potential pitfalls and accounted for them, in which case I would retract my comments. But from what I have seen, nobody is considering how realistic this plan actually is.

If you want to do it, assemble your own team of people you know and trust, fund it yourself, and don't tell anyone about it until you are finished. That is the most likely path to actually finding out something useful, in my opinion.