MOTU came out with Composer which incorporated Performer (later a separate product) in 1985. It was the definitive MIDI based composing system and still is one of the top choices among all professional musicians today (Digital Performer). Limited only by RAM it could run on a 128K & 512K.
So I don't know what you are asking. MusicWorks came out in 1984 and was one of the first music writing programs available for the Mac and was often bundled with 128Ks. However it was geared more toward the casual home user than a serious professional and has related limitations (i.e. no MIDI capabilities). Composer came next and by the end of 1985, there were a dozen programs, though none caught on as well as Composer and Performer.
You are however, dealing with an 86/87 era Mac which by that time some of the earlier programs had gone belly-up and you had a lot more RAM making much more sophisticated programs practical. That's why I say for modern MIDI use, Performer is the way to go. It is applicable to the era of your Mac and is still the standard for professional musicians today.
If you are just looking for a list of music programs from 1985-1986, among the popular originals:
MusicWorks
Professional Composer
ConcertWare
WaveEdit
MacMusic
Delux Music Construction Set
MacMIDI Softwware (MIDIWorks & MegaTrack)
MIDI Composer
Music Shop
MusicType
SongPainter
StudioMac
See this:
http://links.jstor.org/sici?sici=0148-9267%28198523%299%3A3%3C52%3AMSFTAM%3E2.0.CO%3B2-M&size=SMALL&origin=JSTOR-reducePage
AND THIS:
http://www.semaphorecorp.com/ss/ss25.html