You can read about the fall damage here. It is not “non-existent” if you are not in a clan, but if you are in a clan the wrong set of multipliers are being applied which make it appear that way.
To sum up from that thread, here is the main point from @Xevyr
Players who are in a clan will take reduced fall damage, multiplied by the friendly fire multiplier…
Players who are NOT in a clan, will take full damage.
I cannot comment on the other things you have mentioned however.