Hi bignon,
It sounds like East Legon should work for you. It's a large and diverse neighbourhood with safe areas. Without traffic, your wife can get to Cantonments in 20 minutes. Another neighbourhood you may consider that's in between East Legon and Cantonments, and is diverse, "medium/high class" is Dzorwulu. There are a lot of great homes and flats in both. Welcome to GH! 