First off, welcome to the site.
1. Some of the spells work, some of them don't. A spell to bring positive energy into a home could be effective; a spell to make someone grow wings would not.
2. Anyone can, as long as you've learned about magick and know how to properly cast. I would recommend reading and learning more before casting.
3. The best spells are debatable, I suppose. I wouldn't say there are any "newbie spells," to be honest. You're either ready to cast or you're not. However, I wouldn't recommend starting with anything that could potentially hurt people if miscasted (for example, a curse could end up having unintended consequences, such as backfiring on the caster).
If what you mean by "wind spells" is controlling the wind, you're out of luck: almost any serious witch considers weather magick entirely fictional. However, you could draw energy from the wind.