Generally, bumper-sticker length short phrases aren't copyrightable, but some lines from songs and movies are so memorable and essential to the song or movie as a whole that they're copyrightable.
Also, some words are trademarks for products, and those trademarks could include toys such as dolls.
So there's no one-size-fits-all answer to a question like this. It depends on which words you're referring to, each of which should be checked out before you use it by your own IP counsel.
Avvo doesn't pay us for these responses, and I'm not your lawyer just because I answer this question or respond to any follow-up comments. If you want to hire me, please contact me. Otherwise, please don't expect a further response. We need an actual written agreement to form an attorney-client relationship. I'm only licensed in CA and you shouldn't rely on this answer, since each state has different laws, each situation is fact specific, and it's impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue.
Short phrases are generally not copyrightable and can usually be used if not trademarks or service marks. See an IP lawyer for guidance. "Fair use" is a defensive claim made once you are sued for infringement and a case for infringement is proven. It should not get to that if it is not infringement due to lack of likelihood of confusion as to source. That seems vague because you gave no facts. You need to show your dolls and the "line or few words" you want to use to an IP attorney and get advice. There is not good substitute for the advice of an experienced attorney who has seen what is and isn't considered infringement by the courts. The only advice you should rely on from AVVO is to see an attorney, as the purpose of AVVO is to let you look at general answers and pick an attorney, so that you make a better choice of who to go to for advice and assistance in your specific situation.
L2BL: Only your attorney knows for sure, and even then there is room for argument and differences of opinion.
So far, this is free to you. Until you pay a fee, I am not your lawyer and you are not my client, so you take any free advice at your sole risk. I am licensed in IL, MO, TX and am a Reg. Pat. Atty. so advice in any other jurisdiction is general advice and should be confirmed with an attorney licensed in that jurisdiction.
The advice you have received is correct. I would add the following: Any time a client comes to me with a plan to gain commercial benefit by associating her products with famous celebrities, famous songs, famous movies, or famous companies, I warn the client that in all likelihood, the plan will violate intellectual property rights owned by others. For example, while short phrases from songs cannot be copyrighted, they can be protected under trademark law. The phrase "You ain't nothing but a hound dog" and the words "hound dog" became inextricably intertwined with Elvis, and anyone who uses this phrase or these words on a commercial product is almost certain go face a law suit by the administrators of Elvis' estate. In addition to trademark law issues, depending on your use of the phrase, you might be violating rights of publicity belonging to the authors or performers of the lines that you choose to use. Here is the fundamental problem---you want to benefit by associating your dolls with works made famous by others, rather than do the hard work of creating dolls that people want to buy because of their intrinsic value. Our IP laws are designed to reward people who do the hard work of creating original new products, and to penalize those who mooch off the work of others.
Of course, you probably could use some of the quotes without running into a problem---each one would have to be reviewed with IP counsel on its own merits. There is no substitute in a situation like this for working with IP counsel.