Typically for a show it's not in the pedalboard chain at all. There is an XLR Pass through and a 1/4" in, and each of the volumes are controlled independently. I run an XLR from my mic to the Rolls and then another XLR out to the mixer to carry my vocal input. An aux send brings my in-ear mix back to the 1/4" input, so I can mix my vocals independent of the overall mix right at the Rolls. I have a special cable that I had made for me that carries both my instrument line and my headphone cable, so there's essentially only one snaked line going from my bass to the pedalboard.
At home for practicing I just run a 1/4" cable from the end of my pedal chain into the 1/4" input on the Rolls and then purchased an 1/8" to XLR cable on Amazon to get the signal from my iPhone or my tablet to the other channel on the Rolls.
If this is of interest to anyone I'd be happy to start a new thread and post some pics and links. It started out as a quiet way to practice in my apartment, then the band decided to go to in-ears I was basically set up, just needed to buy some better ear buds.