"Are you like her?"
Translation:Você é como ela?
Tu is almost never used in Brazil, except in one pretty rural state. In fact, it's considered kind of rude in Rio--you only use for emphasis, meaning something like "you idiot". Você is used pretty much exclusively by most Portuguese speakers, so I'm not sure why they're confusing things by introducing tu so early and using it so often.
I think I can answer this. 1. No, because Portuguese has many "question" words equivalent to our where, what, who and so on and when they start a sentence it is obvious it is a question. 2. The word "são" is the version of the present tense of ser that goes with they but also with plural you, your sentence starts with singular you "você" and therefore should use the "é" version of ser to be correct. 3. You have answered your own question, "vocês" is the plural you and that's why their sentence used "são". We just say "you" whether we are talking to one person or many, the Portuguese speaker needs to know the number before he or she speaks.
It is not possible to know which one is meant without more context because we use "you" as both a singular and plural pronoun. The accepted answer shown above uses the singular interpretation of "you". The plural version "Vocês são como ela?" is just as valid though. Both should be accepted.