Flemish School triptych: major work by Adriaen Isenbrant, Hans Memling, or 19th-century pastiche?

Leslie Hindman, from the United States, sells on 23 January 2018 a "Flemish School, 15th / 16th century" triptych with the Virgin and Child in a landscape (central panel), and donors with saints (wings), estimated at $8,000 to $12,000. The website has the important addition "Uncertain of exact age of painting. May be later than the 15th/16th century date listed in the print catalogue.". 

My gut feeling is that it is a 19th century or early 20th century pastiche (a fake, we would call it now), based on colours, condition, and some incongruities, but it is hard to be certain based on online photographs only.

The composition is supposedly by Adriaen Isenbrant (ca. 1480-1551). Isenbrant was an important and rich painter in Bruges, one of the last in the line from Memling and Gerard David, before Antwerp took the dominant position in Flemish painting. The above is a work described by the RKD as "Anonymous Southern Netherlands, ca. 1500, free after Adriaen Isenbrant". The central figures are clearly the same as in the work for sale, but the quality here is much better.

I haven't been able to find the original by Isenbrant (I don't own the Friedländer volume on Isenbrant), but other works attributed to him certainly are somewhat comparable to what we have here.

So could this be an original by Isenbrant then? Perhaps, but it isn't the only element we can trace back to other artists.

The Saint Barbara on the right wing is almost identical to a Barbara painted by Memling on the right panel of the Moreel-triptych in the Groeningemuseum. The style of the face is more modern than Memling would use though, more the style of Isenbrant or Jan Provoost, so I guess we can abandon the attractive fancy that this is an unknown Memling triptych.

And this brings us to the for me most damning piece of evidence against this being a truly old masterpiece, a work made in Bruges ca. 1530 or so. The clothing of the female donor is 40 or 50 years out of fashion compared to the man, or compared to usual Isenbrant works.

E.g. these two wings with donor portraits show how the man is quite similar to the one for sale here, but the woman is totally different.

The face of the male donor is quite out of line with the style of the other parts of the triptych, almost as if the painter here instead of older paintings used a real person instead, and had trouble transposing him convincingly to an Isenbrant style.

And of course, as soon a you think to have nailed it with the clothing, you come across another work which shows the danger of leaping to conclusions. The Sedano triptych by Gerard David (where Isenbrant started his career in Bruges), from ca. 1495, shows the two donors in quite similar attire to what we have here. So it is possible to have an authentic work with this type of clothing!

If it is an original Bruges triptych from ca. 1500, it should be worth considerably more than the estimate, and I can't see this then going for less than 50,000€ (more if it would turn out to be by Isenbrant or another big name). But like I said, my gut feeling is still that this is a good pastiche, a skilled late 19th century painter taking elements from some Bruges paintings and creating a new triptych with them. It will be interesting to see the result of this one!