1. it takes a year and a day of study and practice so you fully grasp what you're getting into. you might get all excited after reading chapter one of Cunninghams Wicca Guide and this 'yes! i'm going to be Wiccan!' but two months later, you get bored and it's not so much you decide not to be, but you get into a new show, or life piles on and before you know it, it's 2 years later and you realize you haven't done anything. i hate saying it's a 'phase' but for many people it is. not to say someone who was Wiccan for 3 years decides to leave the path was in a 'phase', it's more for people who are trying to figure out who they are [say high school age] find Wicca and decide to wear it like 'prep', 'jock', or 'goth'. the year and a day gives you enough time to determine why you are entering this path.
2. Wicca talks about many religious things however heaven and hell are not part of Wicca, they are Christian and not universal beliefs. Wiccans believe what you do in this lifetime will effect you right now. we are not working towards an eternal 'heaven' endpoint. most [if not all] believe in reincarnation. reward an punishment effects the now thanks to karma and the Threefold Law [what you do, good or bad, will effect you three times] this law is up for personal interpretation, but essentially it means if you decide to trip someone you don't like, you will receive a return of 3 negative things [some see it as karma] where the next thing you know your favourite shirt rips, your bike gets stolen and a surprise quiz is handed out. others choose to see it as the energy effecting your mind, body and spirit. think about when you're in a bad mood, your body aches, your mind is in a haze, and your spirit is non-existent. either way you choose to interpret this Law, it's how Wiccans see morality and justice.
3. regarding your comment 'there should be an afterlife' not really. no one really knows. an afterlife is really a comforting thing to believe in to try and cope with death. Wiccans know death is part of the natural cycle, and believe energy doesn't die, it is recycled and remolded into something new. life is a cycle, it is circular, and we all all born, grown, and die. it is believed your spirit will be reborn again to live a new life, continuing for an infinite amount of cycles. there is no eternal land of milk and honey after death, some believe in Summerland, a personal heaven where you soul may rest, but eventually you will be reborn. nothing is permanent. and even if we die and that's the end of our spirit, our energy is in our children, our bodies return to the earth, which fuels the plants, eaten by deer, eaten by man and again you see the natural cycle. this might be a strange or scary subject for someone who strongly believes in an afterlife, but not everyone does, and to them, this is a comforting view.
4. a Wiccan/Pagan wedding is typically called a Handfasting. the couple have a wedding with guests and a high priest and/or high priestess, say some vows, make some promises to each other, then they hold each others hands, the priest/priestess ties them together [not too tight] with ribbon, and the couple walks around a ceremonial fire [or jumps over a broom. it's a personal ceremony you could just stand there and a blessing is chanted] then the ribbon is [not being untied mind you] taken off their hands and placed in a box. this ribbon has bound the couple together, and it a symbol of their bond [think of a wedding ring, though pagans do wear those too] if they decide to part ways [aka divorce] they need to preform a different ritual and untie the ribbon to undo the binding.
5. well you can't speak for everyone but the vast majority of Wiccans are fine with LGBT individuals. Gerald Gardner [founder of Wicca] wasn't a huge fan, but this was the 50's where no one really was a huge fan. and yes, once can argue Wicca is about balance, balance in nature is male and female energies, and a union of two men or two woman would upset the balance, however, there are male and female energies inside all of us, so most Wiccan's are fine with LGBT people. really if they're happy and not doing harm Wiccan's don't tend to make a big deal and protest.