Ideas for short stories

I've got some ideas for short stories, and I thought I'd tell you about them, so here goes:

• The first idea is one I've had for quite a while, ever since I saw a guy in Berlin who looked like a future-version of Markus. Basically the idea is that two friends realise their friend has become a time-traveller, and that he's started travelling in time without them, the reader follows the two friends in their search for a time-traveller.
• The second idea is about a zombie with moral-dilemmas, he wants to eat brains, but he knows it's wrong and wants to make his way of living better.
• This short story involves Sille getting lost on the North Pole, then Sofie, Markus and I have to go looking for her.
• The fourth is about a girl who is forgotten by everyone, and has to find a new way of living, she finds out she's not alone and becomes part of a group of chosen forgotten ones.