The PCBs arrived, and I assembled everything. One thing that didn't work was plugging the S2 Mini into the staggered holes directly - you need headers for solid connection. Oh well. Another problem was the overcurrent protection of the new chip, that triggered whenever all the servos moved. Replacing one of the resistors with a bigger value one fixed this.
Sadly, I still didn't get the camera module working correctly, even with the new shield. Oh well.
I used the PCB legs with switches, but I didn't connect them yet.