Well, here's some information from the page "More Information on Fair Use" at copyright.gov.
The law "calls for consideration of the following four factors in evaluating a question of fair use:"
Purpose and character of the use, including whether the use is of a commercial nature or is for nonprofit educational purposes: Courts look at how the party claiming fair use is using the copyrighted work, and are more likely to find that nonprofit educational and noncommercial uses are fair. This does not mean, however, that all nonprofit education and noncommercial uses are fair and all commercial uses are not fair; instead, courts will balance the purpose and character of the use against the other factors below. Additionally, “transformative” uses are more likely to be considered fair. Transformative uses are those that add something new, with a further purpose or different character, and do not substitute for the original use of the work.
Your use may be of a commercial nature, but that doesn't mean it's not fair use. Since you're writing a novel, not a song, you are definitely "add[ing] something new, with a further purpose or different character", and your novel would not "substitute for the original use of the work".
Nature of the copyrighted work: This factor analyzes the degree to which the work that was used relates to copyright’s purpose of encouraging creative expression. Thus, using a more creative or imaginative work (such as a novel, movie, or song) is less likely to support a claim of a fair use than using a factual work (such as a technical article or news item). In addition, use of an unpublished work is less likely to be considered fair.
Songs are "creative or imaginative", so that doesn't count in your favor. But presumably the songs you're quoting have been published, so that would count for you.
Amount and substantiality of the portion used in relation to the copyrighted work as a whole: Under this factor, courts look at both the quantity and quality of the copyrighted material that was used. If the use includes a large portion of the copyrighted work, fair use is less likely to be found; if the use employs only a small amount of copyrighted material, fair use is more likely.
It sounds like you are using only a few words from each song, so this factor counts in your favor.
Effect of the use upon the potential market for or value of the copyrighted work: Here, courts review whether, and to what extent, the unlicensed use harms the existing or future market for the copyright owner’s original work.
Your use is unlikely to hurt the market or value of the songs.
Summary
In favor of fair use:
- You are using only a small and relatively unimportant piece of each song.
- Your work is almost entirely new and different from the songs.
- Your work probably won't compete with sales of the original work.
- The songs you're quoting have already been published.
Against fair use:
- Your work may be "of a commercial nature".
- The songs are a "creative or imaginative" work.
Compare what you want to do to Campbell v. Acuff-Rose Music, Inc. Both of the "against" factors I just mentioned applied in that case, and not all of the "in favor" factors applied; nevertheless, it was held to be fair use.
