Oh, I know it's a japanese defensive form, see it countless times in movies and martial art books, and yes, it thus fits with the mix of japanese and asian inspired forms Jordan used. It's just that Callandor isn't really a sword, just shaped like one, and the DO is fairly unlikely to be holding a sword too. This defensive position was used by samurai in fights against another swordman.

Whelan used artistic license. In part it's for graphic reasons: that form lets him position Callandor below the book title, and it's just a better composition this way.

The other reason is this is easily decodable as a defensive position, which fits thematically. It helps create the impression Rand there is circumspect and knows what he's doing, while having him with a bent leg in front is dynamic and help show his determination.

The "artistic license" bit is that Whelan had Rand hold Callandor as if he intended to use it as a real sword against another swordman. It's not a terribly comfortable position to hold for long a san'angreal while walking (he doesn't even appear to have a scabbard for it, incidentally).

As for Egwene, I don't fully disagree. I think it's more likely to be Moiraine depicted that way, but I also noticed the absence of the blue stone on Moiraine's forehead and the fact she has a white dress. It's more something Egwene might wear, Moiraine usually sticks to shades of blue. Not sure we can trust that very far on a book cover, though.

I think it's more likely to be Moraine, but I won't dismiss the possibility this is Egwene and Brandon/Harriet wished not to make it too obvious because, unlike Nynaeve whom Rand asked to go to SG with him in TOM, it would be a spoiler to reveal Egwene and Rand will resolve enough of their issues for Egwene to follow him to SG and for Rand to trust her to come and link with him.

If I stick to my "pattern analysis" method though, I had noted down (it seemed) Nynaeve and Moiraine would at some point meaningfully work together during the finale, so I'm not surprised to see Moiraine there. Spotting the patterns RJ created through the series has never been very reliable for predictions/theories, though. It's relatively easy to spot repeating patterns when you have all the scenes to compare their common elements (and RJ was very crafty, for e.g. he can have an allusion to Egwene's struggle to be the Amyrlin of a reunited tower disguised as Egwene spotting the ruins of a Tower in the distance and being unable to find saidar the same day to light a flame/fire...), but it's much harder to spot the patterns when you're missing scenes, and even harder to find an interpretation. A pattern is there for Nyaneve/Moiraine among others easier to connect with the LB, but it could just as well be tied to both of them joining forces to go help Lan (or solving their little rivalry over him), or a dozen other interpretations - it won't come clear before reading AMOL.