1. A few containing the tetramethylcyclopropane group. The percent of individuals damaged is very tiny, leading to the obvious conclusion that kidney vulnerability is genetic/environmental.
2. I've heard similar phrases on many forums. Yet making a statement like that without a use context is damaging. The use context of Fluoronoids is smoking/thermal vaporization. Even with care in a vaporizer pipe, 5F-AMB produces both the fluoro-stink on sweat [toxic metabolism/excretion] and physical symptoms of toxicity. Notably, my friend Jakob just tested 5F-AMB on tobacco in a smoking pipe with direct flame and gently vaporized in a vaporization pipe. In both cases the toxic stink was notable exuding from sweat almost 24 hours later, but the day after he vaporized instead of combusting it, the 5F-AMB produced less overall stink on sweat and breath, and the smell itself was missing the worst 'toxic stench' that he was used to from once-an-evening 5F-AKB48.
The observation that both of these powders has no inherent smell means that the toxic scent on sweat and breath is due to pyrolysis/metabolism.
Correctly, most medical troubles caused by these synthetic cannabinoids are CB-receptor related. They can be lethal and they can be dramatic.
However, despite the receptor drama receptors re-regulate.
The ugly problems creep up slower as a user's body becomes ever more filled with fluorinated toxins, which due to the strong C-F bond can't be broken down completely, nor completely excreted.
The rule is that if the liver can't easily break it down and the kidneys can't easily excrete it, that the body tends to dispose of a poison by sweating it out of the skin and lungs (breath).
The fact that a few milligrams of 5F-AMB's partial-breakdown products can still be smelled on the breath & sweat twenty hours later means that the drug is so hard to break down that the liver/kidneys have accomplished very little against those few milligrams in so many hours.
The promise of ADAMANTYL-THPINACA is that it will break down easily and quickly relative to the fluoropoisons.
You are indeed correct that the high-CB2 CHMINACAs can cause major problems, as can the high-CB1 activators such as JWH-018, AM-2201, 5F-AMB.
The problems caused are receptor related however - agonism/antagonism/withdrawal.