All depends on how you like to work really.
From Qu-Drive, you can easily have stereo + click (or more), as separate tracks which you can then adjust & route as required during playback. However, it will take a little effort to create these tracks and save them in the right way. You’ll also need to make up some blank tracks, as the Qu-Drive needs all 18 to be there, even if you’re only using 3. Then the transport controls are quite limited, though if you only want to hit Next & Play at the start of each song, these can be put onto soft keys.
External devices and apps can be much friendlier to use, but getting more than a single stereo out of them, if possible at all, tends to mean spending a far bit dosh on some sort of interface. I’m sure there would be a market for some sort of multitrack playback device with 3 or 4 independent outputs. Many acts opt for a mono backing track + click to overcome this, or if there’s rhythm in the backing, do without the click at all.
I’ve not played with an iPad connected to USB B with camera lead (must get around to that), but a DAW on the iPad connected this way may be a good solution here. Anybody doing this?