offspring (animal), detailed, fine
仔 centers on a young or small version of something: an animal offspring, or something detailed and fine in the sense of being small-scale and precise.
仔 combines 亻 (person) with 子 (child), suggesting a small person or offspring. The extension to 'detailed, fine' likely comes from the idea of something small and delicate.
A person 亻 beside a child 子: think of a small, young animal offspring, or something so small it requires detailed, fine attention.
For シ, imagine a tiny sheep (シ sounds like 'she' in 'sheep') offspring: the little lamb is the animal offspring, and 'she' cues シ.