TIP120-122 are the same, just selected for max collector voltage (60, 80, 100volt respectively).
So yes, no problem to use the 122s instead.
You can use the 127s (PNP). You just have to add eight small signal NPN transistors as well (as in the video).
Makes your circuit more complicated.
Any LOGIC LEVEL n-channel mosfet that can switch at least 1Amp can be used.
They don't drop the 0.75volt calculated for the TIP120, so LED CL resistors have to change as well.
Mosfets don't really have an advantage in this circuit.
Leo..