The IRFZ44N is not suitable at all for 5V gate drive. You should use a logic level MOSFET.
You haven't given any indication of the load these MOSFETs have to drive. Voltage I presume
is 2S LiPo, ie about 8V, but max current? Need to know...
You can probably get away with much lighter MOSFETs than a TO220 package, which will help
with the mass budget.
Some sort of gate current limiting resistor might be a good idea so the MOSFET gate isn't pulling
too much current from the Arduino pin - 150 ohms might be reasonable.
If you want faster PWM than 490Hz, its probably going to be necessary to consider switching losses - a
gate driver chip might be needed (adding to parts count/weight, alas). A MOSFET with the minimum
total gate charge than can handle the max current load would be best.