Heyho there, while digging through the DLL i kinda dug into the map loading again to 1) verify what we may already know and b) associate the data from the files with where they're stored in memory. I started documenting my findings in the wiki (https://github.com/CircleOf8/DllDocumentation/wiki). Is any of the sound related stuff new? I am not sure, really Have a look: https://github.com/CircleOf8/DllDocumentation/wiki/Map-File-Formats#map-extension-file-mapinfotxt
No, it's pretty well known. The reverb stuff is never used AFAIK except in the Earth Node. btw, dry and wet refer to the amount of an audio signal that is treated by whatever effect. If a signal is totally wet, that means 100% of the signal is being treated, and vice versa. edit - I wasn't aware of all those room types, so there's that.