This question is only for Latin American Spanish, ignoring the use of "vos", please. I know that the answer would be different for Spanish speakers in Spain (I think so anyway...)
In Latin American Spanish, "ustedes" is used instead of "vosotros", thus the third-person plural conjugations instead of second-person plural conjugations. But "tú" is commonly used.....
So if I have a compound subject, one of whom is "tú", then how do I conjugate the verb?
Example:
Luis y tú salen la casa juntos. ??? Does this conjugation work, even though "tú" is second person, and (in Southern US English) the sense is "Y'all leave the house together", which is definitely second person plural. But in Latin America, they wouldn't say "Luis y tú salís la casa juntos" ... or would they??