
HaraldKlak |

As I read this spell, your body is comatose while you inhabit your shadow and gain Shadow abilities as if you were the monster.
Do you still retain your original abilities such as spellcasting, class features, etc? Or do you only have shadow abilities?
I would say that it functions similar to polymorph spells. You loose abilities that are dependant on your original form, but retain all those that aren't, including spellcasting.
Spellcasting will be limited though, to spell without material components.

Ravingdork |

RAW is clear that you would maintain almost all your abilities, including spellcasting. However, being incorporeal and without gear (the gear is on your body, not your shadow) might make things rather difficult.
Might I suggest taking Eschew Materials?