Adjectives preceding multiple nouns

Question

If an adjective precedes multiple nouns of different number/gender but describes all of them, which form of the adjective should be used?

Or must an adjective be repeated when describing the nouns to avoid misunderstandings?

Answer 1

1. "Любимые мальчик и девочка" = both are beloved. Correct, but rare form, because it's easy to mess it with 2.
2. "Любимый мальчик и девочка" = only the boy is beloved. Rough implication that the girl is not beloved. This form is often used for jokes.
3. "Любимый мальчик и любимая девочка" = both are beloved. Correct and most common form in collocation.
4. "Мои любимые: мальчик и девочка", "мальчик и девочка, которых я люблю", "любимые дети" and etc. are common in books, since 3 seems excessive on writing.

Misunderstanding when number/gender is equal is a known issue. Speakers try to aviod it. The most famious disambiguation is "Письма знакомой из Киева не заменят фотографии его любимой и милой дочери Марии". In "фотографии его любимой и милой дочери Марии" following meanings are possible:

• Photo of his beloved person, and sweet daugther Maria.
• Photo of his beloved and sweet person, and daugther Maria.
• Photo of his beloved and sweet daugther, and Maria.
• Photo of his beloved and sweet daugther Maria.

And lots of other meanings. They say, it's more than 1000 meanings possible.