My son, who has AS and is ten coincidentally, also has problem with realistic books but loves to read. We tend to pick the same sorts of stories that you have read. DS is currently independently ploughing his way through the Rick Riordan Percy Jackson and The Kane Chronicles books, which he adores and is costing me a fortune .
Books that he has loved over the last year or so, other than the ones you mentioned, are:
The Charlie Bone series (which he read to himself)
Muddle Earth (he read and thought it was very funny)
His Dark Materials (which I read to him and he adored)
The Inkheart series (again, I read)
Elidor by Alan Garner (my childhood fave, which failed to interest him
We are currently reading Neverwhere by Neil Gaiman, which is a bit adult for him so I am skipping over some of the sweary/extra gory bits, but he is absolutely loving the story.
Please help, since finishing the Lemony Snicket series, which we all absolutely loved, we are lost for ideas. We are reading them to my DS at bedtime, he would be too frightened of horrible histories or horrid Henry. They are too realistic for him. We have read the Roald Dahl books, the HP series, the lion, witch and the wardrobe series. He likes adventure, fantasy and funny books. All suggestions welcome. TIA