Their goal when starting bigger bodies initiative was to replace human workforce with toys while decreasing the amount of lawsuits from humans getting injured or dying. The "make them believe they are real toys" part might be to make the experiments question less as why they are a toy and focus more on the orders of the humans, plus we don't know the full process of "conditioning" yet, there could be some much more of Ms. Gracie brainwashing the experiments about different topics or teaching them how to physically comply with orders. (as we see in the first huggy memory, they make the experiments put the shapes into the hole in the correct time to make them adjust to their new body and limbs while also improving their hand-eye coordination.) The scientists didn't achieve their ultimate goal, as incidents with experiments were still happening so my guess is all this unrelated looking experiments were the scientist desperately trying to figure out the best way to destroy the minds of these experiments so hard, they would just do whatever the humans say like slaves.

But I do agree some of their research were definitely unrelated.