Can I use SampleRobot to create an instrument starting with a piece of an audio file?
Like, for instance, a particular note that I really like?
It is possible to import a .wav file in the Samplerobot Montage version and then assign a key range from the sample. Of course if you expect to sample a single note from a track then expect extremely poor / unusable results. Samples/ audio can only be adjusted so far by a system before they become unusable. Most will stretch a single note sample over maybe 3 keys on average to about 6 at a max.
So basically if you want to make a full instrument you need a full sample set of notes. But if you want just some random hits/ effects to trigger on different single keys then yes you can bring a sample in assign it and just trigger that sample without trying to make an instrument from it no problem.