The new character animations for the 2015 summer villains have been released on lego.com. From the descriptions, we can glean quite a bit. First of all though, nothing has changed regarding there only being one Skull Grinder and Skull Slicer, and that the Skull Warriors are horde mode.
Now for the new revelations we start off with the Skull Basher description, "Skull Grinder’s dark power courses forcefully through [Skull Basher's] bones making him the strongest of the Skull Army’s lieutenants." This tells us that there is only one Skull Basher, not many, which would prompt the question, will we get a name?
Next, we go on to the description of Skull Slicer. There is still only one of him. However, we learn something new about his place in the hierarchy of villains, "Skull Slicer is a fast and vicious lieutenant in Skull Grinder’s dark army." So now we have conflicting reports. Product descriptions tell of him being under the control of LoSS, but this says he is in direct service to Skull Grinder. This makes me personally think that LoSS is another of Skull Grinder's pawns, rather than an offshoot villain.
Further, from the description of the Skull Warrior animation, "The Skull Warriors are the rank and file of Skull Grinder’s army. Animated by his dark power, these skeletons shamble relentlessly into battle..." Nothing really new here: horde mode, mindless army, blah blah. However, the description makes it seem that the warriors were not created, but simply zombified. In that case, why did the people of Okoto have a piece of real estate filled up by the graves a bunch of dead soldiers? Who did they have to protect themselves against?
Finally, an excerpt from the description for the Skull Scorpio animation. This one is quite interesting indeed. "A Skull Scorpio is both a tough and sneaky adversary that will lie in wait for days waiting for the perfect moment to spring its trap. The Scorpios usually hunt in small packs using clever pincer moves to surround their prey. Created by Skull Grinder’s dark power..." Now we see a difference between the Warriors and the Scorpios, which apparently there are multiple of. The Scorpios were created, and the Warriors were animated. This could just be verbal variety, however I think that these words are different enough to imply a difference in the origins of the Scorpios and the Warriors. This lends credence to the hypothesis that Kulta the Skull Grinder is using the mask of Creation to actively build his army, and/or that the Scorpios are amalgamations, that they were put together from other parts to make something worse and more heinous.
The link to Skull Basher's animation. The others should be easily found via this link.
P.S. There wasn't anything new or especially telling in the descriptions of Ekimu and Kulta.
P.P.S. Did you know that P.S. stands for Post Scriptum, which is Latin for 'After Writing?'