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That style seems like grim harlequin to me, and its crown store only...
LOL, no.
The Mazzatun style is nothing remotely like Grim Harlequin. The only reason people associate these two styles is because of a bug in which the game's API was incorrectly reporting the name of the Mazztun style as Grim Harlequin. Console users and people using the base game UI without addons never saw this bug, but people who used addons that reported style names did. This bug was fixed in 2.6.4 (it was still present in the final 2.6.3 PTS build). But that's all that it is: a minor bug in the API.
In reality, the two styles are so different that they are pretty much opposites. Mazzatun looks like something out of the Amazon rain forest, and Grim Harlequin is loosely based on a jester outfit.
As for whether or not it'll be craftable, nobody knows, but my guess is that ZOS will, at a later date, add Mazzatun and Silken Ring to the two SotH dungeons, as a way to bolster interest in the SotH content and DLC. This would be consistent with how they've handled previous DLC styles.