im going to use santiago as a baseline because thats where most of the population live
1) a lot of younger people that are starting to work rent apartments, a lot of the older generations have their own houses, especially if they got it from an inheritance, but i would say most of the working class are living renting houses/apartments. Gated communities are a thing in most of chile, and are not neccesarily that expensive compared to other countries.
2) mostly metro and buses, public transit is really good in chile. Outside of santiago buses are the norm, as the metro only exist in santiago. That being said, a lot of people own cars, and theres a lot of traffic almost all day. You could probably google a lot of stuff about our public transportation as is one of the best in latam/the world
3) i mean, when i was a teenager i was in a lot of parties/playing league of legends, i think a lot of people from that age are still doing that, gaming and then partying with friends. recently theres a lot of people doing trekking, or outdoors activities.
4) i cant help you with this one, as i cant compare it to a place ive never been to. Chile is probably one of the most expensive parts on latam, but i wouldnt say its one of the most expensive in the world, you can probably google prices of basic stuff like gas/utilities/groceries and compared i.