"Stop!! Yuuto-kun!" is the title for the prequel of "The Disturbance of a Devil". That title was on the list in the B-T page before the list was removed.
The "mission impossible" SS is
w/c Google translates to
"Ultimate/Extreme!! Onii-chan mask/disguise".
(Sketchy translation)
The newest SS is
w/c, again, Google translates to
"Combat School of Phoenix DX?".
Those are all the untitled SS and one new that is included in Dx.1
So, all in all, the short stories are