baby (especially a girl), infant
孾 centers on a very young child, especially a baby girl or infant. The given meanings all point to early childhood, with a slight emphasis on female infants.
孾 combines 子 (child) with 嬰, which likely contributes both sound and the idea of an infant. 嬰 itself contains 女 (woman) and 貝 (shell), possibly suggesting a woman holding or caring for a baby. The exact historical development is uncertain.
A child 子 beside 嬰, which looks like a woman 女 with two shells 貝 above, like a mother holding precious shells. Imagine a mother cradling her baby girl as carefully as a treasure.
For エイ, picture a baby girl named Amy: Amy -> エイ. The mother calls 'Amy!' as she cradles the infant.