Yes. Good hygiene helps prevent odor and infections.
Yes. Proper hand washing always prtects you from getting many infections.
Risk reduction. You reduce your risk of infection, and thus for complications for infection, by practicing good hand hygiene, getting vaccinated, eating well, and avoiding excess alcohol and smoking anything at all. It is never possible to prevent (absolutely) the possibility of severe infection.
Sepsis. Maintaining good hygiene will certainly help prevent infection and sepsis - but it is not the only factor for developing sepsis.
Yes. Keeping clean, cooking food thoroughly, and staying away from sick people are reliable ways to reduce bacterial infections. A bath or shower washes away bacteria than cause impetigo. Washing hands after using the bathroom (and washing hands before eating) helps prevent infections like typhoid and cholera. Not getting cough or sneezed on helps prevent illnesses like strep throat and whooping cough.
Certainly yes. Viral infections and parasitic infestations as well.
Washing, cook fully. Wash all vegetables fully. Keep uncooked veggies away from raw meats. Wash all meats and all dishes/pans/utensils thoroughly. Cook all meats well (at least 160 f). Use only fresh ingredients. Wash your hands and scrub countertops thoroughly and frequently.
Wash. Wash all food well, cook food thoroughly. If serving meat, you are better off with a steak than ground meat, because ground meat has a higher incidence of e coli. You would have to cook the hamburger well done to make sure you kill off any e coli that could be in the middle.