SSH and SFTP are partly simulated already using rlogin/rcp. Bit a trivia, rcp is is an actual UNIX command that stands for remote copy. The SFTP version is called scp, the in-game rcp command uses the same parameters as the UNIX scp command.
The new code which will use the host templates will introduce a connect command, which will act like the in-game version of SSH, and allow you to specify a username and password for the connection. The rcp command will also be updated to support username and passwords for file copying. The rlogin will remain, which will attempt to always log you in remotely using your current username, as the real-life rlogin command did. Rlogin is no longer used on UNIX any longer, but I thought it would be suitable to use for the game, as it's easy to use and understand.
I doubt I could effectively implement a simulated Bluetooth, as you mention it is a local proximity wireless protocol, which isn't well suited for this type of game. However logging into and viewing data should be possible. As viewing in-game mailboxes will be possible, I'm sure implementing text messages and such shouldn't be difficult.
However, if a hacker did want to read text messages, it might be more effective to hack into a carrier server and read or intercept the messages from there. In the real world, cell phone companies do store a record of all text messages sent through their system.
As for specific app data, such as Facebook, it would be easier to just hack into that user's account directly on the website. :). These days, all the information stored on our mobile phones are also synced into the cloud. Take the recent iCloud hack, where hacker's were able to grab user contact data, and photos they took, among other data.