A normal mosfet is fully on with a gate voltage of about 9V.
Any "logic level" mosfet turns on at 5V, and often already at 3.3V.
Adafruit has this one: https://www.adafruit.com/product/355
Sparkfun has this one: https://www.sparkfun.com/products/10213
All the mosfets that you mention are "logic level" mosfets, they will work.
It is no problem to use a 60A mosfet for a 0.4A motor.
The flyback diode can be a slow rectifier diode such as the 1N4001 ... 1N4007. The slow rectifier diode is fast when it gets a forward current peak (I learned that on this forum).
You could draw a picture how you are going to connect all the GND wires and show it to us. This topic mentions star-grounding: Common ground and why you need one