If the youngest is 7, you need to involve them much, much more. This is not about making your life easier, it's about making them resilient and capable with life skills. Stop rushing around getting them ready. Make them responsible for their own stuff. If they go to school without homework or a permission slip, they will miss out on something or miss recess, and they will learn. It will not stop them from getting into college, and it will not signal that you are a bad mom! Kids need to fail once in a while in order to learn that they can survive it and the world will not end.
Divide the week into chores, and rotate the kids through it. There's no reason why one can't set the table, with another one starting the dinner, and another loading the dishwasher. As the table is cleared, the breakfast dishes get put out. Everyone gets a week with a chore, then they rotate. They can negotiate and trade chores as long as it's out of earshot and you don't have to know about it or referee it.
They are all capable of sorting laundry, loading the washer and starting it, as well as folding and putting away. Put a different colored laundry basket in each kid's room or closet, which they are responsible for getting to the laundry room. Folded items go in the right colored baskets and back to the room. Stuff that gets left on the bedroom floor doesn't get washed, or they wear it to school wrinkled. It's fine.
If you have stepchildren, then you have a spouse. You don't mention here what that spouse does. Maybe you need to look at that. Why are you responsible for 5 kids on weekends and your spouse is not? If you have a head full of stitches and a returning chronic condition, I wonder why you didn't take a few days off and have someone else take over.
School - is there no bus transportation provided? Can you carpool with another parent so you don't have to go to 3 schools every day? Can lunches be made ahead, maybe 2 nights a week, and sandwiches put in the freezer? They can be popped out in the morning and they will thaw by lunch time. Kids are perfectly capable of taking things out of a snack drawer and a freezer and putting them in a lunch box. You can also have starter foods available for when hunger hits at 6 PM: fruit, cut up carrots/celery/peppers and a pack of humus for a protein-rich dip. Do you have an apple slicer? A great hack is to slice/core an apple in one motion, put peanut butter in the core space, and fold up the apple again. Secure with a rubber band and it will not get brown. Poof! Instant snack for lunch boxes or return time.
Cook on the weekends - all hands on deck. That means kids, spouse, stepkids. Crockpot meals, family favorites in casserole form (lasagna, Mexican bean/tortilla/cheese meals, shepherd's pie, quiche/frittata -- all are forgiving if you don't have exact quantities of one ingredient or another, and all slice and reheat well. Those who aren't cooking can divide up large bags of snacks into lunchbox-size packs - it's cheaper, and if you use reusable containers, you cut down on trash & expense.
One of my friends put a towel bar on the back of each bedroom door - it got the wet towel off the floor even if someone didn't make it down the hall to the bathroom to hang it up.
Does everyone have a hook for their backpack and coat, a place for their shoes, and a basket or bin for their shoes and mittens and other essentials - all by the exit door? It makes cleaning a breeze and it makes each kid responsible for their own stuff. Have another bin for "stuff not put away" - things get tossed their by you, and if your kids want them, they can sort through and do an extra chore as "payment" (mop the floor, wipe down a bathroom, run a dust cloth across the family room furniture).
You are not a failure as a parent, you are not a lazy person, you are not a slave driver. You are building skills and independence in your children. And new studies are showing that kids do better and are less stressed in their teen years when they are not overly dependent on a parent to do everything. They feel less lost when adversity hits if they've always had to do things to take care of themselves.