Any wiccans believe we don't know what the Divine is?

Far from it. It would depend on the path of the particular Wiccan you are asking. I believe in many deities, but that is my choice. Reincarnation is not really our choice, it happens when we have not completed our lesson for a particular life time or still have lessons to learn. You throw the term mother nature, Summerland and the the planets as the GOD(S)/GODDESS(ES). I suggest you do learn more before writing your paper. I also suggest you concentrate on one aspect rather than all. I can answer specific questions, but I won't do your homework for you. I won't even do it for my son!