Even if there is a deliberate effort to place it in the prime universe, realistically the new series is going to be in it's own unique "third universe." New costumes, sets, and more importantly a new creative team.
This would be even more so if the series is set in the JJ-verse, we only have four (soon six) hours of this universe, much of it devoted to the flashy special effects. Relative soon the new series would exceed the three movies in hours of content. it wouldn't be a case of the new series being in the JJ-verse, it would be the JJ-verse that would be in the new series universe.
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