Yes, that is all normal behavior. mine will eat upside down it is something special like turkey.
The snakey tail thing is something they do when they see something new or when they are hunting.
Mine do the snakey tail when we play with the feather toys
Feathers-Sweetie, Sklyar Blue, Mister Peanut, Big Mack & Ibo
Fur-Widget, Gadget, Guinan, Mr. Spock, T'Mir, Micheal, Flower & Pappy
T'Pol, Pandora, Elizabeth & Curzon
TY, TJ & T'Pring
Forever in my heart, Gizmo, Tucker and the rest of my babies over the