Hey Tobi, what do you mean the edges are dry? Not sure I know what you mean.
You are right about those three options. If your edges are slipping out from under you it could be any combination of technique, snow condtions, and edge sharpness. It's likely a combination of all three.
You can still have sharp edges for park as long as you have a bevel on the base edge (at least 1 degree). The bevel is what makes the board's edges forgiving for rails/park. Check out this article for more info on edge bevels:
http://www.boardworld.com.au/content/category/your-tuning-shop/ (read the section on edge angles).
I wouldn't suggest sharpening your edges after 5 days of riding. If you keep going at that rate you will be peeling too much steel and shortening the life of the board. What's better is just using a diamond file to deburr and keep the edges clean and sharp (this won't remove much steel). Do you have a file guide? Do you have any edging tools (gummy stone, diamond stone etc...)?
If you have any questions let me know.