They is an attractive woman
They are an attractive woman
Neither feels right to me.
1. The people who insist everyone must use plural pronouns to refer to they/them do not have any concept of your question. Friend, you use such strange words. What is this English and grammar thing you speak of?
2. They are so concerned with which pronouns I should use to refer to them that they overlook any concern about what adjectives I would add when referring to them.
Edit . . .
To clarify. You are referring to use of the word "they" (and possibly "them"). I wouldn't want anyone to misread and think you were referring to the words "attractive" or "woman".