I am researching a way to send out a PWM-ed IR pulse from an xBee3 device. I couldn't find any IR related libs, so I guess I'll have to "brute" force it by "waiting" X many microseconds and setting digital I/O pins ON and OFF. 
Any ideas/pointers/references would be much appreciated!
MicroPython on the XBee3 RF products won't be capable of the microsecond timing you're looking for, and the PWM output only allows for setting the duty cycle, not the frequency.
You would need to add extra hardware to convert (for example) the I2C interface to IR transmission.  The XBee3 RF products don't support a secondary UART like the XBee Cellular products do, but if they add that feature you would could have a UART->IR interface via a secondary microprocessor.
How can one achieve an arbitrary frequency and duty cycle PWM-ed IR transmission in an xBee3 using MicroPython?