Which gadabuursi has J haplogroup
There is no J haplogroup Xeebjire. Unless you are referring to @NidarNidar maternal haplogroup. FYI his mother isn't Xeebjire (but another Gadabuursi clan). Also, both my Xeebjire grandmothers are N1a. As for paternal haplogroups all but one tested are T1a.

Yes; he exists.
Hostage style take over to envisioning seems to be working.