Azelor, thanks for the input!
For clarity, the deadlands are barren, ash covered rock. I'm under the impression that vegetation cant grow because of the lack of sunlight.

I didn't actually know there was a different between biome and environmental attribute s, to show how Newby I am. And yeah! mangrove works well with my idea of the location.
But I'm unsure of what geographical elements in missing /what woukd be affected by mountains that I would need to showcase. If my understanding of weather patterns is correct, one side of the mountain range woukd be more lush and green while the other experiences a desert.

Id also like to make sure my geography makes sense, I mentioned I had some tectonic maps that were tragically destroyed by a well-meaning sibling, so I'm basing my mountain ranges off of what I remember and acting accordingly.