I knew most of what you posted but the information about the advance map's ini I did not know about, and proved quite useful(Thank you)
I have done some more research and testing, and some of your results are off.
The first byte is the encounter ratio. Then we have 3 filler bytes (?) followed by a pointer.
After the pointer, we have our 12 Pokémon with their minimum and maximum levels. Bytes are in this order: minimum level, maximum level, Pokémon number.