Gittin 86: Handwriting, Witnesses, and a Common Get

2 mishnayot bookend this daf, with some "end of the tractate" outlandish cases: 3 types of gittin that are not good, but they are good enough to prevent children from a future marriage from being mamzerim. Basically, when the text is lacking in some way. Plus, why witnesses sign a get - namely, to prevent the husband from denying the get, for example. Also, the Gemara attempts to determine when the husband's handwritten get suffices and when it does not. Also, 2 husbands sent 2 wives divorces via messengers, but they have the same names. Or even more... Now what?