I’m very interested in this project! I am currently doing something similar with a PIP board from China, in combination with a MinimOSD. The system works well but it limited by the capabilities of MinimOSD. The PIP board has 4 camera inputs and I can remotely switch between full screen views of any camera and multiple camera layouts.
The PIP board I’m using weighs 34g and I’m using a Micro MinimOSD which I think weighs 10g. How much will your complete system weigh?
My PIP board is mounted under the frame, just behind the gimbal.
At 2:20, I pan the GoPro around to see the camera inputs of the PIP board: