My concern with class AB amp for your speaker is in the range between 45-1000 Hz, where EPDR dips to around 2 ohms. There are tons of contents in music/movies in that range, so some class AB amps may struggle. In terms of current, lower EPDR than the impedance does not increase current, but could result in a lot more heat in the output devices so not a good idea.
This is a good example of using power, that is watts, is not the best way, as for people who are not familiar with EE principles may not realize that if an amp is rated say, 100 W 8 ohms, if that rating is limited by the rated current, then it is current limited at current = square root (100/8) = 3.53 A, then into 2 ohms, the "power" is only 3.53^2*2 = 24.92 W, that's not a whole lot! It is a reverse double down thing, so 100 W 8 ohms, 50 W 4 ohms, 25 W 2 ohms.
Simple math yet can confuse people right!
That's why I always want to calculate voltage and current requirement, not "power". Rule of thumb is, for higher impedance, voltage is more important and for lower impedance, current is, but that's just rule of thumb, there's always something in between, though the Ref 1, in the bass and midrange, it is current that they need, the tweeter do want voltage but it peaks at 16 ohm, that's not a concern.
As far as your concern about sibilance, lean, warm etc., I don't believe those things are due to power amps in the calibre of those you are looking at, if someone says they could hear the difference between ATI's class D and AB, I just smile, knowing full well, with confidence that they would not hear the claimed differences in a well controlled DBT, I respect enthusiasts like Richb, but I always just though they could imagine things better than I lol... I know people would say even their cats notice the difference when they change their amp, what can I say....sorry I digressed, should have just stick to EE principle and shut up on the rest.