@AltCode It's tough because there's no direct #ActivityStreams object type for a collection of Notes.
"as:Article" is like a longer note, and "as:Page" is a generic web page.
"OrderedCollection" would fit but is a stricter sub-type of as:Object and I'm honestly not certain what other implementors would do if I served that up.
Its omission in FEP 1b12 might be unintentional, or it may be purposeful. Starting a separate thread about this...