No they don't, but I am worried that it might be more difficult to get the TARDIS here than we originally thought.
It's possible. It got easier once my mum knew the truth. Then we didn't have to worry too much about when we came back to London. Though we always tried to not make it seem like we were gone for too long, for my mum's sake.
More like a parallel world. It was very similar to our own but with small or sometimes it could be major differences.