Brandon pretty much expressed exactly my thoughts on the biome issue. This is the same reason I want to do the Earth continent equivalence zones for species. Need an plant or animal? Just look up what's the the corresponding area on Earth an you know exactly what kind of things live there. Much easier than keeping track of a list. Also, prevents things like kangaroos and rhinos from hanging out with grizzly bears. Plus, there is so much data we can just use instead of making up our own!
As for having another species...
On real Earth, there were five species alive ~250,000 years ago (the time frame I suggested we start), Homo sapiens, Homo neanderthalensis, Denisovans, Homo floresiensis, and Homo erectus. However, all were gone (one way or another) by approximately 40,000 years ago. Personally, I prefer to keep it that way. Adding another species into the mix takes the focus away from "How would civilization be different on this planet?" to "What would happen if XYZ didn't go extinct?" If we wanted to do a scenario like that, it would make more sense to just use regular old Earth. Changing both just creates too many variables for my taste.
Also, I'm still working on the geological detail map. I'm hoping to finish it this weekend.
