The answer to many of these questions are going to depend on which Wiccan (or Wiccan tradition) you're talking about. Neopaganism in general tends to be a very personalized religious path unless you're associated with a specific tradition that expects you to adhere to their rules. The vast majority of Neopagans (including Wiccans) are solitary, though, so I can't emphasize enough that answers are going to vary widely. Disclaimer aside...
1) This feels like the wrong question to ask because it presents something of a false dichotomy. You need to understand that in Neopaganism in general (including Wicca), the divine isn't understood to be wholly transcendent. It's immanent; that means that deity isn't separate from nature in the first place. The Wiccan God and Wiccan Goddess in particular are strongly tied of natural cycles and forces. Wiccans will often choose to work with other deities, though, and some of these may be less of what we would call "nature" than others (i.e. Hephaestus, Athena).
2) Neither. Wicca is predominantly duotheistic, or centers around two principle deities: the God and the Goddess. Beyond that, some Wiccans are also polytheist or possibly henotheists, but very rarely do you see strict monotheism in Wicca or Neopaganism. While others might disagree with me on this, I personally think that if you do not honor the God and Goddess you probably shouldn't call yourself Wiccan. Much of Wiccan mythology centers around that male-female dynamic, and I think removing that radically changes what the religion would be about.
3) This is one that is really going to depend on the individual practitioner. However, it can be said that Wiccans (and Neopagans) often have a more ecocentric ethic than mainstream society. This means that "harm none" is not applied only to humans, but also to the nonhuman world. Clearly it is impossible to actually live by this ethic; you can't live without causing harm. It's a paradox each person who follows the Rede needs to sort out on their own.
4) Generally no, but an individual practitioner might object to it. There are some who abide by the philosophy "my body is my temple" but I usually see this manifest as basic healthy living, not extreme prohibitionism. If anything, Neopagans and Wiccans are hedonistic (and I don't mean hedonist in the negative sense, I mean it in the philosophical sense).
5) Typically anything that violates the Rede is not allowed. In simple terms, no curses, no vindictive motives, no revengeful power trips, etc.
6) The distinction between a "spell" and a "ritual" can be fuzzy sometimes, IMHO, but Wicca has a wide variety of practices beyond what most would call spellcraft/magic. Things that honor the God and Goddess, the Lunar Cycle, the Solar Cycle, you could all consider to be rituals. I'd say these are the focus more than spellcraft. If you're looking to just do spellcraft, it isn't necessary to follow Wicca. There are plenty of magical traditions out there that don't have the more overtly religious elements attached to it.