-snip-Also I would like to draw attention to dry spell which I don't see how Yin could possibly be better or even equal to.
How would Yin affect opponents cards that are 1 hp, like damsels, parasites, phoenixes, etc?
Thats what I figured. I guess the only other question that I have, would be if they would stack or if they would be like Nightfall/eclipse
Since these are spells they can't really stack, but yes, if you cast 2 Yangs then the creatures will receive +1|+1 twice