Open-air paludarium

[Yemeyana]

My plan for my desktop paludarium involves two tanks - one to my left and one to my right - with the left one flowing into the right vie a waterfall that goes over a wall-mounted shelf. The waterfall (more of a watery slope) goes over the area that I use for writing, etc.

Obviously no terrestrial or semi-aquatic animals will be used, but I want some semi-aquatic plants to go 'in' this system. One tank will hold a pygmy puffer or a Betta, the other some small inverts (I'll be covering the intake...). The home-made filter draws in from the invert tank and out into the betta/puffer tank, allowing the 'fall to flow constantly. The larger tank will be custom made to make best use of the small space available. The smaller tank will have a fairly low waterline and a proper waterfall in it.
So, to the questions:

-Do I need some kind of heat lamp over the system to provide for the tropical plants? The water in both tanks will of course be heated like in a regular aquarium.

-Also, what about lighting? I'm sure I've seen aquaria with overhead spectrum lights, are they adaptable?

-Will splashing be an issue? Could or should I use an extra piece of glass as a 'shield'?

-I'm operating under the assumption I can use gorilla filler foam and grout for the rocky landscape, and it will be watertight. Is that okay?

It's a small but big project that I'm sure will hold many learning curves, but I'm finally set on what to do with this project.