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.
creative - having the ability or power to create; a creative imagination. originative. original - being or productive of something fresh and unusual; or being as first made or thought of; a truly original approach; with original music; an original mind.