I haven't ever heard the aurum cantus driver and has limited info about it.
If I were building a center with the dayton reference woofers, I would probably use a smaller one, like the 6" or even the 5". The 6" is surprisingly slightly more sensitive than the 7". First of all I would pick a smaller driver because midrange, especially the vocal range is generally better reproduced by a driver smaller than 7". And also the dayton reference woofers have nasty break-up at a fairly low register so you either need a high order crossover (3rd or 4th) or you need a incredibly low crossover point.
Now I prefer low crossover points because I feel they image better, but I still don't like being limited by the woofer.
For the tweeter, I haven't heard that particular morel tweeter. but if I were going to spend $66 on one, I would probably instead go all out and spend $87 for a
Scan Speak 2905-9500.
This is in my opinion (and in several others) the best tweeter for the money.
Off the top of my head (i.e. with out any calculations) I would probably go for 2 dayton 6" reference woofers in parallel and the Scan-speak tweeter in a ported box of about 1 cu. ft. volume.
Now 2 of those woofers will be slightly more sensitive than the tweeter so you can either tweak that in the crossover, box, or just enjoy the extra bass/mid-range.
For the crossover I would probably go 2nd order (for cost) or 4th order at between 2kHz and 2.5kHz
2nd order is cheaper, but you may still hear woofer break-up, and you need to wire the tweeter in reverse polarity.
4th order would elimate any woofer break-up and would make any driver misalignment problems minor.
About the biwiring questions, all you would have to do is have biwire binding posts on the box, and connect the tweeter to one pair, woofers to another.
Bi-wiring (2 pairs of wires) is pretty much worthless and can actually make things worse.
Bi-amping (2 pairs of wires running from separate amps) can be used, but this center won't require enough power to need it. It can only handle about 120ish watts music, 80 watts rms test tone. So I wouldn't recommend bi-amping.
Anyway I'm pretty much rambling at this point, so i'll stop.
PS. This speaker design may have lower a fairly low impedence depending on the crossover design. So you may have to play with it to get it to the impedence you want. Although raising the impedence helps out amps, it decreases the sensitivity of the speaker which doesn't help amps.
See, here I am rambling again...
