Using %'s to describe a ketogenic diet isn't very accurate. Usually anything under 50g of carb is ketogenic. If you eat a whole lot or very few calories, the %'s could take you far over or far under 50g of carbs.

Protein only affects ketosis insofar as consuming too much, like more than 2g per kilo of ideal body weight, some will be turned into glucose. That would be like more than 112g of protein for you.

Insufficient protein results in the body breaking down your muscles, including your heart muscle, in order to keep the brain functioning. I have no idea how long that takes or how low you have to be... and I don't care to find out through self-experimentation.