Mostly in boots you'll find a difference in how stiff they are, softer flex for less response, and little flex for high response. Generally the stiffer boots are for high end faster riding, park riding generally is softer. But honestly if you buy a pair of mid-range boots then they will be pretty much in between and good enough to use on any terrain.
As for stance and stuff depends on the person really, when I did my courses as an instructor it was suggested we rode duck footed, not always equal its up to you. Personally I ride +18 -18 equal as I ride switch alot, but many people dont, so long as the front foot is angled more than the back it's up to your preference, alot of people have around a 5 degree difference on the back foot. If your gonna ride freestyle then you should keep the forward lean settings low, more high performance and make them higher. I rode the 06/07 cartels on the f5 setting for most of the season which is pretty high but it keeps you flexed and in a better position.