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.
A muse is someone who engages the artist on an intellectual level, spurring him or her to run with creative ideas that someone else wouldnât really understand. To be a muse, encourage the artist to explore more deeply, rather than pulling back. No discussion should be off-limits.