^No, because "myriad" means "uncountably many" and thus cannot possibly modify a singular noun. There's no such thing as "a Myriad Universe" -- only one of the Myriad Universes.
When I first got the gig to do an Abramsverse novel, I thought of it as the equivalent of a MyrU project, but then I realized it required a different approach. MyrU novels tend to be grounded pretty strongly in Trek continuity -- they show us characters, concepts, worlds, and events we know from the mainstream continuity and explore them in altered forms. They're alternate takes or deconstructions of a continuity that the readers are assumed to be familiar with. But the Abramsverse novels need to keep their continuity references to a minimum and tell self-contained stories that are accessible to readers who know little or nothing of the existing Trek continuity. Also, there's the fact that the Abramsverse books are all nominally in the same reality as one another (even if they don't directly connect to each other), whereas each MyrU novel is a separate timeline.
So yeah, in a broad sense, the Abramsverse can be counted as one of the myriad alternate "universes" (aka timelines) that coexist in the Trek multiverse, alongside the timelines seen in the MyrU novels. But in terms of storytelling, they're significantly different.