Plausible Vs. Impossible
Gus Goose runs so fast that the chair seems to vibrate with his impact. The Plausible is that if you sit down hard enough or fast enough the chair can tip or move because of the impact. Its impossible because the chair wouldn't really vibrate back and forth no matter how hard you sit down. It might tip over or sway back in forth, but it won't shake the entire seat along with the thing sitting in it.
As Gus Goose shuffles the bread and salami, it makes a wonderful and very large sandwich. It's plausible you can shuffle thin, flimsy objects: such as bread and salami. It's impossible because in reality, you can't really shuffle bread and salami. The bread would most likely fall apart or not spring up and down as much as a deck of cards would do.
As much as everyone would love to knit their spaghetti into a lovely sweater before the ate it, but it's not quite so easy. It's plausible though, because in theory you could knit spaghetti. It has the same shape as yarn has along with the stringiness of it. It's impossible because you can't really knit spaghetti because its spaghetti and not yarn and it most likely would not stay together. Its also very unlikely for it to all be one giant string of spaghetti.
Gus Goose is dipping his bread into Donald's coffee and soaking it up for a little extra flavor. This is plausible because bread is absorbent and if you dipped in coffee some of it would soak up into the bread. Its impossible because the bread would not fill it's self up with all the coffee in the cup. In reality, there would still be coffee left and only the piece of the bread that was dipped would be filled up with the drink.
After Donald feeds Gus Goose the meat that says "How to get rid of Hungry Relatives", Gus's stomach starts to go crazy. This is plausible because your stomach can make crazy noises, even some sounding like a dark barking. It is impossible because you can't actually have a barking hot dog in your stomach that makes you bounce around the house after a cat.