Any switch can do, as long as is a momentary switch.
Where is that circuit board located?
Bottom left corner of the Gauge cluster.
How hard was it to get out?
Simple, Beginner soldering skills.
How did you get it out?
Follow the LED swap Procedure.
What's an XLR connector? How was that used?
An XLR is a connector used for Profesional Audio, it's just used for quick disconnect.