I don't think Immersed is really necessary because they aren't putting Fauna in the bowl, and I'd presume it's a small bowl based on the title. I think the bowl could work as long as the plants receive some light. If not try and place it in maybe a south facing window, I'm not sure what side you currently have it in (but I can probably assume East since it receives its light in the morning).
Also about the substrate if your potting soil is Organic then you can use it. But I would recommend instead of play sand go for a darker substrate like the black aquarium gravel they have at Petco.
The Fraternity of Dirt #97Just because its dirt doesn't make it low tech
Emersed tUB clUB #17