| Quote #7
Maria's plan to forge a love letter (in order to trick Malvolio into believing Olivia loves him) furthers the play's notion that "epistles of love" are not to be trusted. Maria's forged letter is not so different from Duke Orsino's messages for Olivia (which aren't necessarily forged but are contrived nonetheless).
| Quote #8
Feste's claim that sayings are like kidskin ("cheveril") gloves suggests that words are easily twisted or turned inside out. Feste's right, of course, and he's a master of witty wordplay, punning, etc. His remarks about language (and his spirited twisting of words throughout the play) are in keeping with the spirit of Twelfth Night festivities, where the world is temporarily "turned upside down" and inside out.
| Quote #9
Here, Feste demonstrates perfectly how words can be rebelliously twisted and turned inside out (compare to 3.1.3 above). The clown picks up on Viola's use of the term "dally nicely" (play subtly) and makes a joke about a "wanton" woman (a woman who "dallies" or sleeps with a lot of men). OK, so what? Well, we could argue that Feste implies that language and wordplay can be dangerous or seedy, like a "wanton" or "disgraced" woman. Or, we could argue that Feste's wordplay suggests that screwing around with words (Shakespeare's job as a professional playwright and poet) is just as entertaining as literally screwing around. An even better answer? The passage holds both meanings simultaneously.