I don't have any guidance, but can tell you about my imaginary friends; I like Pokemon, and there are two pokemon called Plusle ( like a pink rabbit with a + for a tail ) and Minun ( same but blue with a - ) and I made two up called Timesus ( green with x ) and Divido ( yellow and etc ) and I used to talk to them. And before them, I had imaginary dogs and rabbits, and whenever I made up a new one I would send the old one away to live happy lives.
I just read the symptoms, and it sounds like me. But I'm not going to worry too much about it. My daydreaming hasn't really affected my life too badly, so I'm not gonna diagnose myself.