As to carrier frequency, the motor noise I'm refering to is audible noise. On PWM power, motors tend to squeal and sing and if that motor is in an air duct in a hospital, the noise will be most unacceptable. If it is on a factory floor next to a stamping press, the motor will not be heard regardless of carrier frequency. Thus, I say, use the lowest carrier frequency the application will tolerate. Higher carrier frequencies shorten motor life somewhat, sometimes force a derate on the drive output capacity, and definitely increase radiated electrical noise (EMI and RFI). I have never found any benefit at all with carrier frequencies above 8Khz.
Drive/motor lead lengths are another rather complicated subject. As a general rule, longer motor leads, smaller hp ratings, and higher power supply voltages make the insulation stress worse.
In a 460VAC environment, motor leads on a 10hp motor of 60 feet or more and on a 100hp motor of 250 feet or more result in voltage pulses often approaching 1400 volts. I don't have specific data on other voltages but I think it would be logical to assume the same proportional increases occur. If your motor is built to withstand these levels of pulses, you will be ok. If not, well........
In view of the above, a NEMA motor rated 460V has to pass a test with high frequency pulses of 1600V to get an MG1 Part 31 endorsement. A conventionally rated motor is tested at 1200V sine wave.