TO PERSONALLY ADDRESS NUMBER FOUR: Walking at 3 mph is clinically proven to burn the most fat calories. If you are trying to lose weight, you DO want to stick to low intensity exercise to reduce fat. Unless you're running marathons every day, you'll never burn through all your ingested carbs PLUS your stored glycogen in order to get to the fat. Low intensity exercise uses aerobic metabolism, which breaks down fat along with glucose.
This is a good layout to start a routine! Pretty basic. Switch up the cardio & abs often so you don't get bored, find creative ab workouts online!