I was so set on Evelyn. This is going to be hard if the baby is a girl. Maybe he'll come around and see that it's a great way to honor his grandmother.
Well, can you still use your original name and call her Evie? Or some other NN? My LO has a nn and the only time I'm using a formal name is at doctor's appointments and registrations (benefits documentation, plane tickets, etc).
By the time your daughter might want to "grow" into her more formal name, it will be years later and hopefully time could make DH see what a wonderful gift that his grandmother lives on through your LO.