Amazing, everything works!
Tender:
I realized that the tender only needs one wire to the engine as both wires in the tender go to the engine frame.
Engine:
Made a brass tab for the ground as the manufacturer only had a piece of wire wrapped around the screw.
Hooked up the contact for the sound cam and used two sets of 2-wire connectors from lights4models.com: one to disconnect the boiler from the frame and another to separate the boiler from the front boiler cover that has the marker/head lights and electronic components for ease of maintenance.
Sound and lights are all working