I don't know. Even though I'm a bit leery of it right now, I have one aqua chorus in my Crystal Beast deck, but I haven't tried this out yet since I don't use Rainbow Dragon and am afraid of clogging the spell/trap zones up. I guess it depends on whether it is still considered as monster once it is in the other zone.
I just looked at one of the crystal beast's card's text, and it says it is as a continuous spell card once it goes to the spell/trap zone, so I guess this means no. Would be good for Aqua Chorus if it does work. Right now, I'm afraid of it helping my opponent, but since it's a fun deck, I can't help including it because it's even better with Jesse's The Ties That Bind skill.
yea i just experimented with it. unfortunately it doesnt increase the monster of the same name if ones in the spell/trap zone. oh well. thanks for answering so fast! :)