A good writer wants you to experience the world as if you’re there, and paints a picture with words to help you do so. So the use of bass, tenor, contralto, mezzo and soprano where voices are concerned is all just to add color for the reader, so that s/he can “hear” the voices in his or her imagination. In this context, these terms have nothing to do with singing voice, and everything to do with the pitch as heard when they speak.
We’ve all heard a woman with a light, flute-like voice, like a soprano; or one with a deeper, huskier voice, like an alto/mezzo or contralto (the later is even deeper and rarer). Or guys who speak with nasal, high tenor voices or booming, resonant basses. So a writer will shortcut it by saying the woman said ‘hello’ in a throaty contralto and, if you know what a contralto is, you can ‘hear’ it yourself.
I think the use of “deep” to modify “contralto” is redundant. I mean, duh, that’s what a contralto is – a low-pitched female voice. It does serve to define “contralto” for anyone who doesn’t know what it means, though. But “lilting” isn’t necessary to a soprano voice; I’ve known many a high-speaking gal whose voice wasn’t very musical or melodious.
Nicole Kidman is a good example of a soprano speaking voice; so is Lisa Kudrow, Goldie Hawn, Meryl Streep.
I’d put Michelle Pfeiffer as a low soprano or regular mezzo, certainly not a contralto. (Contralto is lower than mezzo / alto.) Oprah Winfrey is a mezzo, I think, though I think some might fairly describe her as a contralto. Elaine Stritch: definite contralto.
Let’s look at the Simpsons/Futurama V.O. actors. Dan Castellanetta as Barney: high tenor, maybe even counter tenor. Almost all of Hank Azaria’s characters are tenors, I’d say. Phil Hartman: baritone. Billy West as Fry: tenor. Billy West as Zapp Brannigan: baritone. Kelsey Grammer, baritone. Harry Shearer as Derek Smalls, Principal Skinner and Rev. Lovejoy: baritone/bass. Harry Shearer as Ned: tenor. Harry Shearer as Julius Hibbert: bass. (Shearer is the best at using different pitches, methinks.)
As a tangent, you really can’t judge the sort of singing voice one will have just by listening to their speaking voice. For example, I tend to speak quite low in pitch, and a writer would probably call my voice a mezzo, perhaps a lilting mezzo when I’m in a good mood. 
So back when I used to sing, people were always surprised to hear my high soprano range. In fairness, part of the reason for the discrepency is that I use my speaking voice very poorly; many opera singers take special care to speak in a properly produced manner, what my teacher used to call “on the breath” rather than from back in the throat (like I do). The latter can be rough on your throat and tends to make you hoarse after a while. That’s why you may notice that professional opera singers often have speaking voices that are themselves quite lovely, often almost musical, thanks to use of their diaphragms and being careful not to push.
