Thanks for the quick response. I may have come across a solution: fm transmission through the data line.
Guitar-> arduino fm transmitter on one freq, receiver on another->ADC-> nrf24l01+.
With this principal I could communicate between the guitar and pedal board as well as power the guitar (capacitive coupling for AC, inductor for the DC), I just worry if it will mess with the signal going through an ADC->(wireless)->DAC. But a frequency higher then a guitars signal, shouldn't be affected if its significantly higher than it, right?
I suppose I'll have to try it out, lol.
But with separating AC and DC @ 9v, I've come to the idea a 1 farad cap on series will block DC, bit I don't know how to calculate the inductor to block the AC. Any ideas?