I think the mural is only partly finished because Solas does not know how it will end. He has an inkling, which is why it is drawn in that way. He seems to fully expect opposition, as depicted with the sword and he must face it; it could also be a clue for the Inquisitor as to who he is, and what he will be doing. I do believe he wants to tell them, but can't, so he wants them to figure it out for themselves.
As for the wolves: in most tarot cards, a wolf howling at the moon symbolizes isolation, loneliness, and pain.
"The fears of the natural mind".
Lack of clarity — Tension — Doubt — Fantasy
Deception — Psychological conflict — Obscured vision
Confusion — Illusion — Fear — Imagination — Worry
Romanticism — Anxiety — Apprehension — Unrealistic ideas
I had my tarot read a long time ago, and got the Moon with a wolf howling upon a cliff with nothing else in sight. It struck me hard.