Will the Arduino's low clock speed limit wireless transmission frequencies that are higher than the clock speed of the Arduino?
The frequency of a (wireless) radio is its carrier frequency. The data stream is carried on it by modulating that carrier wave in some way: by frequency-shifting, for example. A given processor could not provide data at a rate faster than its clock frequency (at least as a steady-state rate), but a packet of data, once supplied to and buffered in the radio, could then be streamed out at a speed unrelated to the physical specs of the supplier (the MCU). If the MCU had to drive the transmitter, bit-by-bit, then that would indeed limit the transmission speed.