1. They are much alike in character.

2. They are much alike in personality.
(Are both the same? Which word is commonly used?)

3. There is a letter for you from your mother.
(Does 'for you' modify'letter'? Does 'from your mother' modify 'letter' as well?)

1 answer

I'd use 1 more often than 2.

In 3, both prep phrases are modifying "letter" yes.