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 definition of collective is a group of people working together toward a common goal or in an organization. An example of collective used as an adjective is a collective art project, a group of artists working together on a mural. collective. Gram. collective.