Saga Who were the Massassi in Canon?

In Legends they were descendants of the Sith species, but the only thing we know of them in canon for now is that they were slaves of the sith iirc.

Do you think the story group kept the old concept or will they be changed to something else?

 

I have absolutely no idea what the Lucasfilm Story Group and Pablo Hidalgo think about the subject, but here are two excerpts from my yet unpublished 22 page Yavin IV 2015 research study:


Who or what is Massassi?
“The pirate ship soars over the dense jungle” scene has the title “fourth moon of Yavin” but switches to “Massassi Outpost” in the next scene featuring the guard standing on a temple, and refers to the matte painting shot as “Massassi Outpost - jungle temple”. The Great Hall annotation in The Star Wars Portfolio refers to “Massasi stronghold” (in an early script that was the name of an Imperial fortress). No line says “Massassi Temple” which leaves it inconclusive whether Massassi is the actual name of the moon, a codename Rebels used not to accidentally disclose the location of their hidden base (Yavin IV), or the name of the original natives and/or the Force users that used to live or reign there (according to Expanded Universe speculation, e.g. The Illustrated Star Wars Universe).
Because the sculpting and movement of the gargantuan main stones looks rather impossible, the latter speculation is not without merit. Quite possible that a conflict between the indigenous Yavin IV population and the Force users let to a genocide of the native population.


Possible conclusions from the building materials
The Great Temple’s exterior and interior architecture features noteworthy oddities.
First, it’s obviously a combination of two vastly different construction techniques. On the one hand there are these single gargantuan blocks that defy the imagination of just how they were cut and transported. The base to support these, on the other hand, suggests a rather crude and ancient but feasible and proven erection method, but stands in a considerable contrast (why are the stairway pylons not made of the same material as the gargantuan blocks?).
Second, while rectangular blocks of stones were also used to erect buttresses and piers on the inside, there are also circular stone block pedestals onto which fluted columns (that widen out towards the top and appear to be an abstraction of the local “Massassi tree") with a different kind of rock and manufacturing process rest. The fluted columns look genuine because the Great Hall features their rectangular counterparts near the light slots (there are also identical columns made from metal, but these could have been manufactured by the Alliance - compare image page # 4).
And last but not least, the sculpture in front of the Great Temple has eroded (page # 16), while the conjectural statue of Exar Kun (page # 11) doesn’t show its age of several thousand years.

The inevitable overall impression is that of two techniques and two groups that somehow worked together to achieve a common result but with vastly different tools and methods, where the primitive one provided the base onto which to rest the building elements of the advanced one (both on the exterior and the interior).
The earlier mentioned EU suggestion (page # 10) supports this notion, obviously referring to the Tikal temple ruins seen in two different shots as the Temple of the Blueleaf Cluster (which survived intact, having been built with advanced construction techniques) and the Palace of the Woolamander (having mostly crumbled because of ancient construction techniques).
But (the surviving parts of) the temple complexes feature identical rooftops, cresterias and asymmetrical positioning of the buildings (possibly representing a celestial constellation) and ultimately suggest a common purpose or religious practice; nevertheless divided between a highly advanced caste (of force users?) which frequented the Blueleaf Temple while the common, less advanced natives frequented the Woolamander Palace.