I think you’re confusing fasting and ketosis. They are somewhat related in that you can achieve ketosis through fasting or through diet. But consuming calories will break your fast, but it won’t necessarily stop ketosis. Hope that clears it up.
Yes. Mostly everything stimulates the liver to produce insulin thus breaking your fast. I do however drink a pea protein shake before my strict stop as a meal replacement for dinner sometimes. It really keeps me full-until it’s time to start my eating window.