Is the toy that I took from my workplace for my younger brother—after I asked my colleague to deduct its price from my salary, but she gave it to me claiming it was damaged, even though it was new—considered unlawfully acquired wealth that I must repay?

What the manager did, giving you the toy and saying she would record it as damaged in the papers, is impermissible. This is a breach of trust. It is not lawful for you to take this toy except with the permission of the store owner or whoever acts on his behalf. If he does not grant permission, then you must return the toy, or its value if it has been damaged.