It's not quite clear what your assumptions are, but it appears that you might be assuming that only two "rays" can interfere at a time at any point. If so, that's not correct. Destructive interference doesn't destroy the interfering waves. Instead, interference involves the superposition of all the "rays" incident at a point. I use the term "rays" here because of the way you made your drawing with waves coming into the aperture and rays leaving the aperture.
If, instead, you draw concentric circles around A having the same radial spacing as your incident wavelength, and do the same for B and C, then you might get a better idea of how Huygens principle works. Anyplace that circles from A, B, and C all overlap, you'll get constructive interference. Destructive interference (and interference in general) is more difficult to illustrate graphically, because it requires taking both phase and amplitude into account. Phase change is proportional to the distance from the point source; and the amplitude contributed by each point source drops in proportion to $1/r$, where $r$ is the distance from the point source. Note that this is different from the way that intensity drops, which is in proportion to $1/r^2$. The only way I know to do the interference calculation is to use calculus: to do an integral adding all the phase and amplitude contributions from the wavefront, across all the points in the aperture.
If this doesn't help, please try to clarify your question.