To be frank, we would have loved to get married in Peru, where Mari grew up, and where much of her family still lives. But Peru is alot harder to get to than Mexico. We decided on Mexico City because back when Charles was hip and cool, he lived there and it stole his heart. It is a city that steals hearts.
If you are staying in the recommended neighborhoods of Condesa or Roma, you will be residing in a very safe and walkable area. These neighborhoods are filled with families and young professionals, and are very walkable. Moreover, in the last 10 years, many individuals from the United States have moved to Condesa/Roma and you will likely run into people from the states. Of course, given the fact that it is still a big city, we'd recommend that you avoid walking alone late at night. Stick together.
Yes. You'll be surprised at how many people in Mexico City speak un poco English, especially at hotels and restaurants. That being said, it is not a bilingual city by any means. If you are worried, make sure you are with someone who speaks at least a little Spanish. Mexicans are very kind, however, about you trying to speak their language, and love to engage with English-speakers. Have fun.