Thank you FlapJack and C. Mitra for taking the time to answer.
Well noted for the diode and it is a regulated supply, as you noted and meant.
As for the resistor, please clarify, is it meant to be 200 ohm minimum or maximum? do you mean to choose a 200ohm instead of a 100ohm?
Additionaly, if choosing higher resistance (like 200 ohm), will it cause to additional stress/heat of the mosfet?
So basicaly a decouppling capacitor will short to ground any spike it cannnt handle beyond its low capacitance value (0.1uf)? if adding prior each mosfet/ ic, will it make any influance on the circuit?