Just FYI, I was able to purchase both Del Parro Apartment 20 and Apartment 7 (or you could do 4). You have to walk up to the for sale sign in front of the building.
This may be common knowledge but I thought I remembered @Auth saying you couldn’t purchase in the same building.
It’s really convenient as I’m just moving all my super cars to Apt 20 and I have some random crazy cars in Apt 7. Just drive out and drive back in.