Story identification request - involving time travel, Winnie the Pooh and Alexander the Great!

I am looking for a short story I read years back about a small (maybe 3) group of time travelers who go back in time. I seem to recall the time machine was in the back of a library.

One person would go to stop Christopher Columbus from coming to America, the young lady would go even further back to read Winnie the Pooh to Alexander the Great, and … I forget what the 3rd person did.

But the aftermath was very interesting, especially how the Native Americans grew as a people when left alone to do so (floating tent homes, advanced tech, etc).

Thank you for any help 🙂

EDIT: I read this as part of an anthology (something like ‘Century’s Best Sci-Fi’ or something similar)…going back 10+ years at least