Latching circuits - problem above input voltage
Circuit 1: VGS max is rated as 25 volts for Q2.  At 30 volts, your gate source junction is breaking down.
Circuit 2: When you push the button to latch off, P channel voltage is momentarily pulled up to [power input - power input * 15K/(100K+15K)] as @sstobe says.  At 16 volts, this is about 2 volts, so you never turn the MOSFET off (VGS(Th) can be 2 volts from data sheet).  You have to pull the gate voltage up to within less than this value.