Mexico City has extremely affordable and good quality fibre internet in central areas (where you would want to live anyway), and the food options are amazing. It's as safe as long as you stay aware of your surroundings and use a taxi service. Many parts of Mexico are safe to travel, especially in high tourism areas. I assume the property would be in the Condesa or Roma area. You'll see americans and europeans walking around everywhere and feel quite at home.
"assume the property would be in the Condesa or Roma area."
I hope so. Polanco is too snooty. The Historic Center has gotten viable for living with residential redevelopment and revolutionary traffic calming but still has a touristy vibe. I like family-oriented Del Valle but it's probably better for a 40 year old than a 20 year old.
Coyoacán's ayuntamiento discourages short term residents and has driven almost all hotels out of the area, but would make a good location close to the National University and lively streets and parks.
