Greetings Roxanne,
Extending the eaves sounds like over kill to me.
Why don’t you just cover the window well with a clear plastic or glass?
You might try diverting the downspouts to a dry well.
Without seeing your problem it’s hard to tell if extending the eaves will solve the problem but, there is no reason that I know of why you couldn’t extend them.
But, I would stick with covering the well. What happens when the rain water hits the side of the house?
Good luck,
Jason