OP's looking at this creatively, not realistically, he knows they probably won't add new buildings, but if they did where would they be is the question.
Nothing in his post suggests he expects anything else other than new properties being created in currently empty areas. What post did you read!?
There are no apartment type buildings outside of the city, I can't believe R* will just cram some more apartments in LS.
No, like Brian B's comment said "there will be new apartments"
He obviously meant there will be new apartment units.