PP means Power Plant. An African sativa dominant strain. Top plant. Good outdoors and in.

Humidity does matter if it is too low because you force the plants to transpire (release moisture through their leaves) in an attempt to raise the humidity itself. It won't do damage but It will mean your plant is working less on growth of bud formation as it's wasting it's time transpiring.

As for the other questions I don't know cos I'm still a newb.