No one knows for sure how many are urban legends and how many are true.

LtS is right about rats not barfing. Not related to vomiting, Warfarin is a major rat poison. Warfarin is basically Coumadin, an anti-coagulant. Rats squeeze through some very narrow spots and their rib cages compress, not without some minor and normally insignificant bruising and tearing. When they're loaded with anti-coagulant though, they bleed to death.

The astronaut/beans thing is (I believe) partially full of hot air. They're probably not worried so much about space suits. Even a pressurized cabin is only pressurized to a fraction of what it is at ground level. If someone has intestinal gas, and the ambient pressure drops rather quickly, they're going to be in some serious discomfort. Since the suit has already got to deal with the change from earth to space cabin pressure, an occasional fart in a space suit shouldn't be a big deal. You're gonna have methane anyway because people just fart.

The Bruce Lee thing (#17) is right, because I just heard it on TV recenttly.