Looks like an interesting project! I can see a couple of problems with your mosfet module:
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The 10K resistors from each mosfet gate to ground don't do anything useful and should be removed. However, you DO need a resistor (I would use 1K in case of interference pickup) from the TC4422 input to ground, to hold the mosfets off until the Arduino output pin gets configured as an output.
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When the mosfets turn off, the flyback diode in parallel with the motor gets a pulse of current equal to the current that the mosfets were passing. So you need a diode that is rated to stand a repetitive 200A surge. Use a Schottky diode.
The TC4422 should be OK to to drive all 5 mosfets. The switching time will be limited by the 20 ohm gate resistors. Expect the mosfets to dissipate around 10W each @ 200A, so good heatsinking will be needed. I suggest you use the AUIRLZ1404 instead f the IRL1404, it has lower Rds(on) so will generate less heat.
It might be better to use a lower PWM frequency to reduce switching losses, say 20KHz. It's hard to know what the switching losses will be without trying it out and using an oscilloscope to measure the switching time.
Layout will be critical. The wires between battery, motor and mosfet should be laid out so as to minimise the area enclose by the complete circuit (battery - motor - mosfet - battery) to reduce inductance and also to reduce interference caused by the switched current. I suggest you build both mosfet modules as a single unit, and ground the Arduino and associated circuitry to the mosfet module. Otherwise, the grounds of the mosfet modules will have a lot of differential noise due to the switched current, which makes driving them both from one Arduino difficult.
I suggest you measure the DC resistance of the motors to determine their stall current. If it is much higher than 130A, then consider implementing hardware to cut the mosfet drive when the current sensors detect a stall, so that you are not dependent on the response time of the Arduino.
What is the reason for the 100 ohm resistors in series with the Arduino inputs used for the switches? Also, it's more usual to wire switches between the pin and ground so that you can use the internal pullup, and only use an external pullup resistor if you need a lower value to reduce interference.
I suggest a resistor from the wiper of the throttle pot to ground, as a safety feature in case the pot wiper has an intermittent contact to the track.