This is an excellent work, and very easy to follow and read through. You should consider placing this in the Wiki or Project section.

In a sort of backwards way, I had one of those aha moments out of this thread.

I had thought the ANSEL turned on/off the AtoD for a given pin - certainly my comparators have been working with the corresponding ANSEL deselected? I had a similar discussion with Melanie & she considered them digital....
This is absolutely true for the outputs (i.e. comparator output) as they will be either high or low. This is, however, not true for the inputs (i.e. comparator input) as your are using their analog nature to compare (in your case) against a reference (this is also alluded to on the post you mention);which is what I was referring to (ANSEL.6 and ANSEL.7). In summary, comparator outputs are digital, comparator inputs are analog.

This is what was nagging me; something does not look correct, yet it behaves correctly (maybe). Then came the aha moment. You run the analog signal through the schmidt triggers effectively converting it from analog to digital. Then you feed the signal into the comparator. So why do you even need a comparator? You really don't, BUT, for your system you really need some sort of comparator (not an analog one, a digital one so you can trigger on its change of state). And, perhaps unbeknownst to you, that's what you created. By letting the comparator input pins be digital, you created a digital comparator (sort of like a logic gate) - very cool.

With that said, you probably could save the schmidt triggers and run the analog waveforms straight to the comparator (they would have to be conditioned / buffered before hitting the comparator). But you have the concept working, so I would not change it now.

Again, very nice job.