I do not think there is PMC(power management controller) bean in PE, if you want to control Kinetis to enter low mode for example VLPR, LLS or VLLSx mode, I suggest you refer to application note an4470 and it's corresponding example code.
You can download an4470 and an4470sw from the website:
http://tinyurl.com/l2p5b7b
Regarding your second question, for Kinetis K family, the maximum power voltage is 3.6V, we assume that the Kinetis family is powered by battery in hand-hold application, when battery runs out of energy, the voltage will drop, this is most cases. So we take a lot effort to design for lower power application. but we do not take a lot of effort for the High voltage application, so there is not high-voltage detect system.