With future perfect (F2) you jump to a point in the future, turn round and say some action is finished then. Actually a complicated thing and cumbersome and in most cases you can express the same idea much simpler without using F2. This tense existed in Latin and it was imitated by writers.
In current English usage, muse can refer in general to a person who inspires an artist, writer, or musician.
The muse is that coupling point or grounding point were the offspring of the inner marriage is more or less exactly matched with a point in the external world. It is what allows us to simultaneously both to hold a single point focus and ground the flow of our creative life energy externally.