I would use some sort of moss. My only experience has been with the common Java Moss, and this manages in low light but also seems fine in more direct light once settled.
Hornwort will fall apart with the addition of any chemicals. Otherwise it is said to be easy and hardy. I believe many do find it constantly drops its needle-like leaves though. Could be the chemical issue.
I would not use Anubias close to the light, as this is bound to cause brush algae. Anubias is best in low light or indirect light/shade.