Ok, that's very odd that they don't show up at all, did you add the two body entries to body_default? The body entry 3EYES is needed for the Sirocco, and GUGBODY for well the gug creature.
They are located in the Readme file, but I'll post them again here.
[BODY:3EYES]
[BP:EYE1:first eye][CONTYPE:HEAD][SIGHT][EMBEDDED][SMALL]
[BP:EYE2:second eye][CONTYPE:HEAD][SIGHT][EMBEDDED][SMALL]
[BP:EYE3:third eye][CONTYPE:HEAD][SIGHT][EMBEDDED][SMALL]
[BODY:GUGBODY]
[BP:UB:upper body][UPPERBODY]
[BP:LB:lower body][CON:UB][LOWERBODY]
[BP:HD:head][CON:UB][HEAD][SMELL][HEAR]
[BP:RUA:right upper arm][CON:UB][LIMB][RIGHT]
[BP:LUA:left upper arm][CON:UB][LIMB][LEFT]
[BP:RLA1:right lower front arm][CON:RUA][LIMB][RIGHT]
[BP:LLA1:left lower front arm][CON:LUA][LIMB][LEFT]
[BP:RLA2:right lower back arm][CON:RUA][LIMB][RIGHT]
[BP:LLA2:left lower back arm][CON:LUA][LIMB][LEFT]
[BP:RH1:right front paw][CON:RLA][GRASP][RIGHT]
[BP:LH1:left front paw][CON:LLA][GRASP][LEFT]
[BP:RH2:right back paw][CON:RLA2][GRASP][RIGHT]
[BP:LH2:left back paw][CON:LLA2][GRASP][LEFT]
[BP:RUL:right upper leg][CON:LB][LIMB][RIGHT]
[BP:LUL:left upper leg][CON:LB][LIMB][LEFT]
[BP:RLL:right lower leg][CON:RUL][LIMB][RIGHT]
[BP:LLL:left lower leg][CON:LUL][LIMB][LEFT]
[BP:RF:right foot][CON:RLL][STANCE][RIGHT]
[BP:LF:left foot][CON:LLL][STANCE][LEFT]
If you have these parts try checking the error log and telling me what it says. Once in a while gugs, ghouls, or ghasts wouldn't show up, but that was when they were competing for locations more.
I never had any problems having the Sirocco come up.
Also, just for the purposes of reposting part of the Readme and my wordy directions:
The files: creature_obsidean.txt
language_SIROCCO.txt
should be placed in your Dwarf Fortress Directory under
\raw\objects
The File sirocco.txt should be placed in your Dwarf Fortress Directory under:
\data\speech
The contents of the file sirrococreature.txt should be
pasted into the file entity_default.txt
And the contents of the file sirrocociv.txt should be pasted
into the file entity_default.txt in the \raw\objects folder
I suppose I could make a version more easily installable through modbase, but it worries me because it's been discontinued, and it might not work with later versions.