Will generic lightning cables and the "authentication chip" present in the genuine cables work with iOS 8?
For your first question, fake cable manufacturers are probably aiming for lots of sales, and explicitly stating that it only works up to a certain OS version would turn many people away. (the original cable doesn't have a version limit, so this one seems weird, I'm not buying that)

For your second question yes, this adapter has the useless authentication chip/whatever crap in it, and since the micro-USB standard (fortunately) doesn't have any of that nasty stuff you can plug in any cable from any charger and it'll work assuming the charger itself is good.