Hi Rubini,
On your questions:
1) The only way I found to fix Earth's rotational direction is to invert the texture file, and put the whole solar system upside down in the solar system editor (one of the Nexus modding tools that ship with the game). You probably hadn't noticed it yet, but the whole solar system revolves in the wrong direction: clockwise instead of counter-clockwise.
I've done it on my end with the help of Arparso's texture convertor application (sorry Arparso, I keep forgetting the name of it

), but the conversion didn't turn out perfect for the _bump textures of Earth. Also, since I'm an astronomy buff myself, I edited a Sol system file where the so-called biggest known dwarf planets are included and updated alot of distance/size/angle numbers of the planets and moons, based on info of NASA and wikipedia. Of course, with that Earth texture fix now the rest of the sol system planet textures are upside down.

2) I can be wrong, but I *think* the orbital speed of the planets is correct. But the game calender moves to quickly. At least, that was my observation when checking the date progress in astronomical view with Marcus' diary enabled. The date progressed faster then one Earth day revolution.
As on 3), Arparso already said it all.