The kit control plate would be quite hard to modify as you’d need to find a suitable PCB mounting pot with the correct pin spacing. You nay be able to modify a standard pot by twisting and cutting the lugs, but finding and using one designed for PCB mount would be easier.

But the vintage style plate would be far easier to modify with standard guitar/bass components. You really need to decide if you want to keep the functionality as per the original, or whether to reduce it or change it completely. You could have the pickup selector switches, a master volume and master tone control. Or a volume and a pickup blend control and use the switches to bring in various preset tone cut options. You are only really limited by the size of the control cavity and having just two knobs and three switches. Those sliding switches aren’t the easiest type of switch to use quickly in a live situation.