Am I correct to assume that a 3 way design will give the listener a much better chance to hear the full audio spectrum as opposed to a 2 way design?
Depends on what you mean when you say, full audio spectrum.
If full audio spectrum to you means more prominent low frequencies, than in my opinion I think you would have a better chance of achieving that with a 3-way design, though not necessarily a much better chance. As far as the speakers you have listed, the cello should have 3 db more low end output due to it having two dedicated low frequency drivers, at volume levels approximately 83 db or less (measured at 1K Hz) depending on the dynamic range of your source material and many other factors.
But with any real world test, the proof is in the pudding, so the only way to really know is to do an actual listening comparison.