Very good! I think it would be better and without double meaning. A salada dela (da mulher) A salada dele ( do homem) A sua salada (de quem ?)
"Sua" is for feminine nouns, "seu" is for masculine nouns. Since salada is a feminine noun, it takes "sua".
"Teu" is in reference to "tu", "Seu" usually in reference to "você" (although it may also mean his, hers, its, and theirs becomes of the historical issues associated with it being a 3rd person pronoun).
tua for singular feminine things that belong to tu.
sua for singular feminine things that belong to você, ele, ela, vocês, eles, elas.
Tua is second person. Sua is second or third person.
Is it correct to say Tu/ Teu is used evereywhere except Brazil, and in Brazil its Voce/ Seu.. Mean the same thing just used in different Portuguese speaking countries?
Actually, we use tu/teu/tua (2nd person) in Brazil, but it's used only on the Southern Region of Brazil, which includes the states Paraná, Santa Catarina and Rio Grande do Sul. Pretty much everywhere else in Brazil você/seu/sua (3rd person) is used. I believe in Portugal they use the 2nd person regularly as well. About the other countries that speak Portuguese though, I have no idea.
The possessives must agree in gender and number with the thing that is possessed, not with who possesses it.
seu - singular masculine
sua - singular feminine
seus - plural masculine
suas - plural feminine
It is always "sua salada" because "salada" is feminine. It has nothing to do with the salad belonging to a man or a woman.
It can. How was the question presented to you?
"Salada" here is a reference to the dish, which is a jumble/mishmash of ingredients. That's how you get the vernacular/popular "salada" as a reference to a jumble, but I'm not sure it would work here with the possessive involved.