I'm sorry for your losses, remember your grandmother and uncle and the positive effects they had on your life and the lives of others they knew.
That's strange that you say your fear of death is not as great as to an unbeliever, because most irreligious people I know don't fear being dead at all. I know when I stopped believing there was an afterlife, a lot of my emotional anxiety over it just melted away.
People are cremated because once there is no more mind in the body, it's just dead tissue. It takes up space and can spread disease. Burying it is one way to hide the smell, but it still takes up space, and isn't cheap. Plus some people find it comforting to know that the matter that composed them (or their loved ones) will end up back with the matter that's around them or the places they love(d).
Cremating isn't the bad thing that the Nazis did to the Jews. Murdering them is.
George Harrison was cremated, as was Albert Einstein and TS Eliot, according to their wishes.
If a god exists, and it's omnipotent, then it could magic you up a new body. Why do religious people put so many limits on their omnipotent god(s)?
To ensure burial, write a will, have life insurance to cover the cost of burial, including a plot. There may be circumstances where burial can't be done, like if you die in a plane crash, or if there's an infectious disease outbreak. But most likely, a will and the funds to cover a burial should be sufficient.