I know you can reply to inbound messages from whomever, but (without a Contacts app) there's only 12 Friends to choose from when you want to initiate a conversation. Hmmm twelve.
No, I am pretty sure you can do others. That 12 are the ones you initiate to the most. You are lucky to have that many friends you need to text that often. I am going to have to stretch a bit to fill it unless I put in co workers.