a_G That sounds like a good solution, yeah.
Regarding changing the 4 inputs from analog to digital, the difference is as follows.
The analog inputs are perfect for reading your classic CV signals, which are a variable voltage between a maximum and minimum (0-10V in the case of Pepper). This is read by Bela through the analog inputs and can have any value between the max and min.
Digital inputs are more like the clock or trigger signals on modular synths. These signals have only two states, normally 5 or 0V which can be read by Bela through the digital inputs as either ON or OFF.
When you configure the last 4 input channels to be Digital it means that they are good for receiving clock or trigger signals which only have two discrete states. When they are configured as such the last 4 potentiometers still remain connected to the analog inputs of Bela so you can use them to control synthesis parameters or something. They will not affect the digital signal you have patched in to the inputs.