Can ESP and out-of-body phenomena be understood as a form of dreaming or hallucination?
In some form yes if patient is mesmerized by visual heartbeats, acording to Sciencedaily. Also is connected to someones beliefs. But in my opinion could also be induced by drugs in mices.

So, out of body experience could be umbrella term for more than one phenomenon. Some of them could be caused by hypnotics, some not. I'm not sure if those experiments could negate afterlife, because all of them are conducted while subject is alive. It is not that kind of experimental design.

1) Jane Aspell and Lukas Heydrich. Turning body and self inside out: Visualized heartbeats alter bodily self-consciousness and tactile perception. Psychological Science, 2013

2) University of Manchester. "'Out-of-body' Experiences May Come From Within." ScienceDaily, 24 Aug. 2005. Web. 1 Sep. 2013.

3) Jason J. Braithwaite, Dana Samson, Ian Apperly, Emma Broglia, Johan Hulleman. Cognitive correlates of the spontaneous out-of-body experience (OBE) in the psychologically normal population: Evidence for an increased role of temporal-lobe instability, body-distortion processing, and impairments in own-body transformations. Cortex, 2011;**

4) Disturbances In Brain." ScienceDaily, 6 Mar. 2007. Web. 1 Sep. 2013.

5) http://www.pnas.org/content/110/35/14432