Those are jutsu that affect what is within one's sight. The mirror would be the victim. It's no different than saying that by looking at a picture of Eric and using Amaterasu the real Eric is killed.
Using mangekyou techs on water/ice would be suicidal. Lol.
I just realized that the two examples given here... Are far different.
It is not the same at all. Looking at a picture of Eric is not at all changing the light scheme; in fact, you are honestly just looking straight at an object that does not reflect light, refract it, or even create a reflection of something (certainly not to the degree of a legit mirror).
If you look at a mirror, what you're focused on is what is reflected by the mirror, basically, whatever the mirror is reflecting.