RJ11 is the standard telephone port for POTS (Plain Ordinary Telephone Service) system. In Allegheny County, Verizon owns the POTS network. They do not wish to keep this network running, but I am guessing there is something legal requiring them to support their current customers. However, moving customers, and new customers will not be supported. If you insist on Verizon providing you with home telephone service, you would need to look to an apartment that would allow you to select FiOS, and have termination as RG6 coaxial. This is because using FiOS telephone requires their router to plug into. Since that is not an option, it makes no sense to run telephone lines everywhere. This is a waste of money and space.
You have a couple of options if you want a home phone service. The first is to acquire a cellular ATA (Analog Telephone Adapter). A number of cellular companies offer such an ATA for service. However, in my opinion, this will be rather silly, and it will just make more sense to have a cellular phone then. The second option will be to use VOIP (Voice Over Internet Protocol). You would use an ATA that is either unlocked (and you have to provide the credentials), or through a closed provider such as Ooma, or Vonage for Home. You plug your phone into the ATA, and then you plug the ATA into an ethernet jack.
Since internet will be included, the VOIP option will be a good one. This is again assuming that you need a home telephone number. I have a home telephone line using a Wifi Phone instead of the ATA, and it is by choice. I could just as easily rely exclusively on my cellular phone for telephone calls. If you decide on a home phone, and want everyone to access it, it might be good to provide the phone in a room everyone has access too, or have multiple phones. Obviously, with the studio, it will make sense to have just one phone.