Can "ta" in this situation not be "that" as well as "this"?
In this sentence you clearly point at certain tea, so 'this' is correct. With that it would be 'Czyja jest tamta herbata?'.
If I put "Julesa jest ta herbata" does it become "This is jules's tea"? Or would that just be "Ta jest Julesa herbata"? How would you ask if this is Jules's tea?
ta herbata jest Julesa (your sentence is correct but word order sounds poetic")= this tea is Jules's
to jest herbata Julesa. (you need to in this sentence) =this is Jules's tea
ta jest Julesa =this (one) is Jules's.
I got "Whose is the tea?" That didn't seem so right, wouldn't it by "Czyja herbata jest ta?" That would mean "Whose tea is this?", right?