i have done it 3 times now, always with a small company, and always with the cast playing the instruments.
I love the show, i think its fantastic, but I dont think it works with a big chorus, i've seen it a couple of times with, and it always seems . . . . wrong.
for the production I did with Pain and Panic, (photos
here)
Cast wise, we had
Captain Tempest (didnt play)
bosun Arras: (bass, guitar and keys)
Science Officer (played bass, trumpet and trombone)
Navigation Officer (played keys, bass and guitar)
Narrator (was on prerecorded video)
Cookie: (played guitar and drums)
Prospero: (played keys)
Ariel: (didnt play)
Miranda: (played sax)
Lt Hugo S'Thair: (played drums and cornet)
Cast of 8 not including the prerecorded video. Worked really well, was very tight harmony and music wise, and lots of swapping going on, but worth it. Tentacles were 25ft long fabric filled with balloons and thrown on from the wings. Very very cheesey but worked perfectly.
if your cast arent playing then I wouldnt bother miming- the instruments aren't scripted, so there no need.
If you want anymore info let me know
xx