In above schematic;
- what value should R1 have? is it even needed?
- do we need that pull down resistor(R2)? if yes, 10K is enough or we need higher value like 100K resistor there?
It's better with resistor so output driver isn't stressed to its maximum limits. Gate has its capacitance so it's better to limit charge/discharge current for such weak source
As the gate is basically capacitor, it has really big input impedance. Without pull down resistor it'll be catching all kinds of EMI (electro-magnetic interferences). So 10k is fine. The 100k might be less unreliable if the mcu output is not active (boot/reset)