Merion said:You are correct, of course. According to this page however, Forgotten Foes has stats for shriekers. And these I wanted to add to the encounter (the idea being here, that the shriekers wake up a plethora of other fungal creatures).
Also my question concerning dependencies still stands.
Dependencies.
Certain monsters may reference a spell or something else from an "official" product, so those specific cases will report errors. In general, if you have the Bestiary Bundle, you should have all the licenses needed for *most* creatures.
Shriekers and Forgotten Foes
Contributions to the Community Pack are made voluntarily by the members of the Community. It is quite possible that not all of the contents of Forgotten Foes has been added. It may be anywhere from "a few" to "all". Filtering the races list on "Forgotten Foes" .. it looks like only the Grimlock is there.
For Realm Works use
You may want to note the presence of the Shriekers under "Obstacles" .. as you would a trap. They add to the overall CR of the encounter, but really don't participate in combat -- so their absence from the HeroLab portfolio should not impact running any combat too much.
If you still feel like you want to have a HeroLab entry for it, you could create it yourself in the Editor. A relatively simple monster like the shrieker would be a pretty good first project choice.