I don't know what the difference is between a /6 fork leg and a /7 fork leg (which an R100S is); sounds like a logical substitution to me. Could be the fender mounting?
Tach; I think going with the electronic tach is another fine substitution. Takes care of the gear, washer and instrument in one fell swoop.
Brake arm, OK.
That list doesn't mention the instrument housing itself, which I understand is NLA.