So, I am trying to figure out whether I can only say 你 呢？or whether I can add to that and say 你 爸爸 和 妈妈 呢？If the second option works, it would be nice to know!
Depend on the context, [(noun) + 呢] could mean "how about (noun)?" or "where is (noun)"
"你" is a noun and "你爸爸和妈妈" is a noun phrase. Both can be turned into a shortened question by adding the final particle "呢". Therefore, saying "你爸爸和妈妈呢?" to ask "how about your father and mother?" or "where are your father and mother?" is no difference from saying "你呢?" for "how about you?" in grammar structure (The question can't be "where are you", since I am talking to you, I know you are here with me)
[final particle] used mostly to make a shortened question by repeating only some element of a previous question
為什麼祇有你來了? 你爸爸和妈妈呢? (Why only you come here? Where is your father and mother?)
說什麼無親無故? 你爸爸和妈妈呢? (What are you talking about having no family or friends? How about your father and mother?)
怎會沒人幫他? 你呢? (How could no one helping him? How about you?)
怎會沒人幫他? 你爸爸和妈妈呢? (How could no one helping him? How about your father and mother?)
Actually, [(noun) + 呢] could be a shortened question by omitting the actual question, presuming people would understand what is being asked.
大家都同意了, 你呢? (Everyone agrees, how about you?) is the shortened form of "大家都同意了, 你呢? 你同不同意?" (Everyone agrees. How about you? Do you agree?)
Since 同意了 is mentioned in the sentence, we can presume asking 你呢? is asking 你(同不同意)?