For most more-intensive gore it'd usually fall under a "mature" rating
here's my personal list for scaling (not at all official)
- blood and low quality gore showing (like losing a limb but the meat has minimal detail) or any type of candy / food gore - general
- more detailed gore, showing organs / intestines and furries with their bodies open up revealing organs / being attacked and losing a limb - mature
- highly detailed gore, such as a character being ripped open or attacked and organs being spilled, any gore including genitals (obviously) - adult
like i said, just my personal rating scale from what i've seen
for being bit in half i would place it as adult / mature according to how detailed you plan to make it
same for losing a limb, general / mature according to detail
exposed ribcage i would generally just leave around mature
shark bites seems to be more general, but it's once again, according to how detailed the injury is
Most of your scenarios are relatively straightforwardly covered by the rating guidelines in the upload policy:
May contain mild violence, but may not be gory, bloody, pervasive, or sexual in nature. Other
Free of sexual fluids, bodily waste, or forced involuntary drug use. Minimal blood presented in a comedic manner or mild, non-violent injury is permitted.
Contains mildly violent or disturbing content that may be disturbing or repulsive to sensitive users. This includes depictions of scary or disgusting content in a horror or fantasy context. Other
May contain blood or bodily waste as long as it is not excessive and not sexual. May contain drug use against the user’s will, but may not be sexual in nature.