Hi TCIII AVD
The good thing about Node Red is that it comes pre-installed on every Rasberry PI default OS. There are plenty of good YouTube videos on how to set it up and make it look good in minutes. I have put a few good intro youtube links are the end of this post.
The coding initially is minimal or optional as Node Red is mainly drag and drop + plus configuration in the GUI. Node Red out of the box can control the Rasberry PI PINs which means it can control camera tilt, lights and thrust motors although my implementation is different and calls python scripts. It can also hook into sensor data directly off the PI. Node Red automatically stores and displays sensor data over time on graphs (e.g. plot of ROV depth over time). The timing interval for plotting is completely configurable.
My current ROV setup - work in progress
In my case the Node Red talks to the sample Python code provided by the supplier for each of the sensors. In each case I have only modified the code slightly to suit the application. I have implemented some sample Javascript into Node Red off the internet for camera display, map display, and virtual joystick functionality.
You are correct the ESC assembly will be added behind the Rasberry PI. With my assembly I am not short of space as everything is very compact and I had originally looked at putting the battery in the top enclosure. I opted not to as I am concerned about minimizing heat and condensation so I am putting it in the lower enclosure.
Sample YouTube Links to Setup Node Red
Regards
Andrew