Since [name]Autumn[/name] is a word name I would avoid [name]Lily[/name], [name]Raine[/name], [name]Skye[/name] ext. [name]Autumn[/name] [name]Sophia[/name] and [name]Autumn[/name] [name]Grace[/name] (though a word name too, but is not too nature like) GL
Purely from a sound point of view, my favourite is the beautiful [name]Autumn[/name] [name]Lily[/name]. However, I’m not sure about the idea of two word names, so I might avoid it personally. [name]Sophia[/name] and [name]Isabella[/name] are both beautiful, and I don’t think you could really go wrong with either in the middle - both flow well.
Some other, less popular alternatives, would be :
[name]Sophia[/name] - [name]Ophelia[/name], [name]Sophronia[/name]
[name]Isabella[/name] - Mirablle/a, [name]Giselle[/name], [name]Arabella[/name], [name]Eleanor/name, [name]Eloise[/name], [name]Elodie[/name].