Hello, thats quite a few issues to consider. Not so much a 'just answer' as a design project.
I will work with you on this for 45 minutes for the amount of your offer, then beyond that level I will work with you on a premium services basis depending on what you want.
That will give you a rough idea of my capabilities.
For now my comment is that a ounce of prevention will be worth a pound of cure regarding the water catchment basin (without a cover apparently)... there may or may not be options.
If you can make a sketch of what you have in mind on a sheet of paper then take a photo of it and attach it here using the paper clip icon at the right end of the tool bar above, or the 'attach files' link to the left of you send button, I can get started with some preliminaries...
then... if you accept that I will spend the remaining 45 minutes doing as much CAD design as I can in that time frame.... more detail will most likely involve a significant 'premium service' offer to cover the significant amount of engineering and component specification work required.
We can go from there if you wish.