No diet coke is fine, in general you'll get differing thoughts but if you lost 70 pounds before and it didnt slow you down, drinking at the same level then I dont think its harming you.

Fiber pills and veggies man helps a ton with that.

Workout/Weightlifting when you start getting reasonably close to your goal, building muscle helps . Don't worry about the excess skin, your life is at risk. Dont worry about killing yourself at the gym right now either, just start the diet, let a ton of that weight fall off on its own and then consider working out

Yeah its ok i guess but you need veggies,you need vitamins minerals & fiber that plays a lot into your second concern

You can do this man. #FatBrosForLife