I think it's all about some unusual specs, like the RG8870's asymmetrical neck shape with Velvetouch finish, as well as the chambered body. I hadn't looked into these models before, so maybe I'm missing what's special here; I'm just guessing.
I'm on their email list, and they wrote about what's involved with the series. This is not one of those emails you can view as a web page, so I don't know if there's a way to link to it. Here's the text at least:
"The new Axe Design Lab series builds upon the latest trends in guitar development, while also inspiring the next generation of advancements through experimentation and innovation. These guitars span everything from standards to j.customs, and they range from ultra-modern takes on existing favorites, to guitars built on entirely new concepts. Whether it’s an axe with incredibly extended range, or a multi-scale guitar decked out with the latest pickups and hardware options, the Axe Design Lab promises unmatched creative possibilities.
Established Theory
With their unique lists of specifications, the RDG71ALMS and RGD61ALET are being carried forward from the Axion Label series to the Axe Design Lab lineup. This uncommon move speaks to the reputation and popularity of both instruments.
New Discoveries
In addition to two existing favorites, the new Axe Design Lab guitars leave little to be desired. All five guitars each bring something special and imaginative to the table, allowing guitarists to tap into a completely new dimension of inventive playing."