I'm missing something in your question I think. The goal, as with all Abrahamics, is achieving the ability to enter Heaven. Each Abrahamic has its ways into Heaven according to tradition, and all are basically the same. Do that which God has commanded, and then with his mercy to forgive your shortcomings you will be awarded Entry into Heaven.
Djinn are other free will creations of God. We don't need their help nor they ours. Satan (in the Islamic view) is one of the first Djinn created and after God created man he refused God's order to "Bow" with the Angels of whom he had become associated with due to his adherence to God's will before this. There is belief that there are good Djinn who follow the religion of God, and there are bad Djinn who are on the side of Satan.
Heaven (Janna) isn't something to be obtained on this earth, it is a place, similar to earth, but perfect without the negatives of this earth. One doesn't reach a point where they enter Janna while living. And to my knowledge no Scholar has suggested that as a possibility.
Vedic tradition is quite different. I would say it being objective is true in that there is no problem with believing anything you want, so long as the core belief is maintained. Scientifically more accurate, I find that one a very large stretch. Reincarnation, while a great thought for those who think this world has something great to offer, is scientifically a bigger stretch than saying our core elements are brought together by a breath from the creator in which we call a soul. I simply do not see anything more scientific about Vedic traditions. Although I don't really like his blatant disregard for the belief structure of religions outside of Islam, Dr Zakir Naik has spent a lot of time showing people of the Vedic traditions that their Vedas are similar to the Quran, yet the practice is vastly different due to forces outside of the Vedas, such as society.
All in all, The answer to your first question is too difficult without answering the other questions first. "Enlightenment" in Islam comes from the realization of the religion being true, most true to be exact. Upon this revelation, we change our lives to do as the creator has instructed in an attempt to enter heaven. If you want to relate it, Accepting Islam in your heart is enlightenment. Once your have been enlightened then you work as an enlightened to enter Paradise (heaven, Janna, etc.). Paradise is the Goal. Enlightenment is the path...
Salaam, and May Allah guide you to understanding.