Funny story to start us off, Arwen
When my little brother was about 4, he asked if his sandbox would be in Heaven. I told him it wouldn't. He said he didn't want to go if his sandbox wasn't there.
Ooohhh, this was tattling gold right there. I immediately told my Dad on my irreverent heretical brother. Dad asked me what I was basing my information on, that his sandbox wouldn't be in Heaven.
Good question.
Dad said that everything that was supposed to be in Heaven would be there, so if that included the sandbox, it would be there. So in the end, no one got in trouble, but I learned a good lesson.
I guess though, I can safely add atheists to the list of things that won't be in Heaven. Not speaking of people who currently call themselves atheists, I can't say if they will repent. But I know no one in Heaven will be one!