Well it is a load of stuff about missisippi.

There are many choices you can make for picking a speech choir piece. A good example is "Geographical Fugue" by Toch.

No, it's a fugue.

A fugue is a musical form. An opus is a musical composition. Therefore a fugue is not an opus, nor is an opus a fugue.

A composer may compose a fugue and give it an opus number. In that case, a specific fugue is identified by a specific opus number in its composer's catalogue:

'Fugue in G minor for organ, opus 99, by Franz Schnitzelgruber.'

Death Fugue was created in 1947.