Ok, strange question I haven't seen - or completely missed.
If I turn an IF real, can I move them out (a la Genies/Simbots), or are they permanently attached to the household until death? The doll in the inventory annoys me to no end (I'm OCD about personal inventory), and I'd rather turn them real and boot them out to keep the best friend status.
I don't think so. Genies and Simbots are moved out because of the extended lifespan, and vampires aren't allowed for the same reason. (I'm not sure about Simbots, having never played with one, but I believe that's the reasoning.) Imaginary friends, though, have normal lifespans and are essentially basic sims once they're turned, except that they can occasionally turn into a doll. Therefore, they are under the restriction that, as household members, they cannot be moved out.
Metro has the final call, of course, but I believe that's the answer.