I'm using MWDF v.4b, playing Taiga Orcs. I've just build a researcher's study, but there's absolutely no reactions available to it. Digging through the raws reveals why. In entity_orcfort_taigaorc.txt:
##################################################################
################## CREATURE RESEARCH LAB ##########################
##################################################################
[PERMITTED_BUILDING:BEASTLAB2]
[PERMITTED_REACTION:COMBINE_ESSENCE]
[PERMITTED_REACTION:CONTAINER_ESSENCE]
PERMITTED_REACTION:CLOCKWORKS
[PERMITTED_REACTION:BRAINS_AND_JARS]
[PERMITTED_REACTION:LOOT]
[PERMITTED_REACTION:CLEAN_ESSENCE]
[PERMITTED_REACTION:TRAIN_BEAST_CROSSBOW]
[PERMITTED_REACTION:TRAIN_BEAST_AXE]
[PERMITTED_REACTION:TRAIN_BEAST_HAMMER]
[PERMITTED_REACTION:TRAIN_BEAST_MACE]
[PERMITTED_REACTION:TRAIN_BEAST_SWORD]
[PERMITTED_REACTION:TRAIN_BEAST_SPEAR]
[PERMITTED_REACTION:TRAIN_BEAST_LASHER]
[PERMITTED_REACTION:TRAIN_BEAST_PIKEMAN]
[PERMITTED_REACTION:TRAIN_BEAST_DAGGER]
[PERMITTED_REACTION:TRAIN_BEAST_WRESTLING]
[PERMITTED_REACTION:TRAIN_BEAST_SHIELD]
[PERMITTED_REACTION:TRAIN_BEAST_ARMOR]
[PERMITTED_REACTION:TRAIN_BEAST_DODGE]
[PERMITTED_REACTION:TRAIN_BEAST_MELEE_COMBAT]
[PERMITTED_REACTION:TRAIN_BEAST_RANGED_COMBAT]
As implied by the comments, these are
creature research options, but they're defined in reaction_masterwork2.txt as occurring at either the DRUIDS_HUT, or the MEGABEAST_CELL, although at a glance I can't spot either of these as being available to orcs.
The orc manual suggests orcs should have access to the crucible. That either means we should adjust the research lab to allow its production (and figure out what science the science/tech-tree is for orcs), or alternatively make it so that crucible and other blueprints can be obtained from raids (which feels more orc-appropriate).
~T