In response to the question, my perception (and what I've been taught) is this: voicing is when you select which voices (lines in music, especially in counterpoint but present in all types) belong in which layers of the music. A basic practice of voicing is bringing the subject of a fugue to the forefront of the texture while letting the other voices fade into the background. Or, in the case of octaves, choosing whether the top or the bottom pitch receives more emphasis (or not emphasizing either more, which is still a decision). So voicing is more about the dynamic organization of the performance.
From what I've experienced, tone is actually quite simple: it is either good or bad. If you would like to find what bad tone sounds like, take the eraser end of a pencil (or something else that won't hurt the piano or you, which is why I don't say your hand) and jam it down from above onto the keys and really press into the keyboard. It should sound quite harsh and ugly. Pianists do this to a lesser degree when they don't release but simply press and press and play way too loud, and when they aim at the keys from above, as I mentioned. In reality, very few complaints about tone have anything to do with tone, it's more a problem of dynamic shaping and timing. However, these things are much more subtle than the simple dynamic markings in the score, and never written in, which I assume is why they get mistaken for tone. In the most general sense, good "tone" results from listening, to others (who have good "tone", e.g. Horowitz, Argerich, Richter, etc.) and yourself (here, of course, your ear is critical). Just keep your ears turned on.