I really like your project and waiting for it, good luck & patience to youM-BAM currently lacks these features, which is why I am developing the HEART map which will show rivers and glaciers as well as fix the projection issues inside M-BAM
I started to fix these issues in M-BAM but realized it was such a massive task I might as well remake the whole map in robinson projection (this is kind of similar to the RQ-BAM project)
You can check the HEART thread in my bio if interested though development is still in its infancy