I looked at the crossover photo. It answers one major question but raises several more.
I expect that a commercial speaker maker would keep its crossover design details a trade secret. I'm surprised that a photo of this is published at all. But it reveals no critical details, so the photo may not matter.
The first answer it provides is that there is indeed a crossover in the Pendragon. But it looks like a high-pass filter meant for a tweeter or tweeters. The input + side begins with a capacitor (its value is not readable). That means it almost certainly must be a high-pass filter.
I don't see anything that resembles a low-pass filter for the woofers. It is possible that one does exist, and that the optional crossover exists only for the tweeters. But there is nothing to rule out the concern I and others expressed that the 10" woofers are driven into break-up without benefit of a low-pass filter.
On the two boards in the photo, the value of one other cap is 10 µF, but the other components are unmarked or unreadable. On the optional board, the Mundorf caps are very large and rated up to 600 VAC, which is unusually high. The Dayton cap on the standard board is probably rated at 250 VAC, which is usually more than adequate. The inductor coils look like they are wound with relatively thin wire, probably 18 g or smaller. For tweeters, that may not be a problem, but it is inconsistent with the idea of an optional high cost crossover board with premium cost parts.
The exact wiring path is not clear to me, but it looks like a 4th order high-pass filter with 2 caps in series with the tweeter or tweeters, and the inductor coils and resistors arranged in parallel. Perhaps there is a notch filter (inductor, resistor, and cap) run in parallel to the tweeter.
We know there are 3 tweeters in the Pendragon. Are they in parallel to each other, or in series? The crossover photo doesn't tell us about that. I'll take a guess that the tweeters are in parallel, but because I have never seen a crossover network for a speaker with more than one tweeter, I'm not at all sure about that.
Now, on to the big question. Is a pair of the optional boards worth $750? Are the standard and optional boards different designs with different component values, or are they the same design with more expensive parts? The photo doesn't answer that.
If the boards are of different design, and the optional board works better, why is the standard board offered at all?
If both boards are of the same design, the substitution of very expensive capacitors will not make an audible difference. This has been demonstrated more than once by groups of DIY speaker builders performing blind listening tests. I was part of one such test. Any claims that exotic capacitors alone make an audible improvement or even a discernible difference are wrong, and I'll stake my reputation on it.