You need the Lightmap samples, the Memory fix can be valuable if the editor crashes often on your machince and you need the editor shaders. You don't need Python neccessarily but it helps packing the map with the python script instead of doing it manualy. So you should get that stuff aswell.
Your terrain and map size:
I would go with the standard map size when making a new map, so 2x512 is the right scale. With this scale you get a map of 1kmx1km what is the size of basicly all official FH2 maps. It is also better to go for a smaller map size, especialy when it is your first mapping effort. I don't want to demotivate you, but even with that relatively small map size you will propably need more than half a year to finish the map. That is if you want to do it right and tbh a quite optimistic guess as you will learn things on the fly and make mistakes from time to time.
Btw:
http://www.realitymod.com/forum/f189-modding-tutorials/69889-how-make-awesome-maps-dem-geo2-image-heavy.htmlThis tutorial explains you how to get the terrain from google earth into your editor. You can model it by hand in theory in the editor, but it is difficult and the google earth approach gives the best results from my POV. Keep in mind that you need some space for your heightmapprimary and the surrounding terrain and that you need to scale it down to make it fit your map. But this is also explained in Fenrings tutorial about heightmaps and I would suggest you to read it carefully. Better read it five times to fully understand it, because otherwise you run into trouble right from the start.
http://forgottenhope.warumdarum.de/tutorials/heightmaps.phpIf you don't have Photoshop you can also use GIMP.