As stairs to the basement drop, the space over is called "headroom". To figure out how much headroom you have at any point along a staircase, multiply the number of steps you have gone down by the riser height of your staircase then subtract the thickness of the flooring, floor joists, and ceiling sheetrock. Here is a diagram to help... Typically you will need to have about 11 steps down before you have sufficient headroom to stand upright. In your diagram above, you could definitely turn the storage area into a utility room and use the current utility room area for a mud room with a door between the two located next to the garage wall. There would definitely be plenty of headroom beneath the floor by that point. The spot RIGHT where you have the words "stair line" would likely have a sloped floor but it would probably only extend about 2 feet into that space so you could put a regular height countertop and a false front cabinet there and use it as a drop zone. Alternatively, you could just continue the stairs on towards the right another 4 or so steps and put the landing beneath where the word "Work" in workbench is. If you waited to make the stairs turn until you reached that point, you could turn the entire utility/storage area into one big mudroom/laundryroom and not worry about sloping floors anywhere. Probably wouldn't want to put the washer and and dryer into the corner where the "workbench currently is" because of the need for drainpipes. But other than that, you'd have a free hand. Of course, this would change how the basement rooms would have to be set up but... Then again, depending on how you plan to use your basement and how easy you want access to it from the main floor of the house to be, there is yet another possibility. That is, turn the stairs around by 180 degrees and start them over where the work bench is. By the time they reached the hall, you would have plenty of headroom. You could probably even shift that little closet toward the garage so that it sits over the stairs tho it would have a sloped floor. But, you could put angled shoe storage on the sloped closet floor and make a positive use of that space.

The pantry space doesn't look big enough to be replaced with a mudroom and half bath. Maybe a hallway and a half bath. Here's a thought - do you need 3 dining areas? A formal dining, a breakfast room, and a full bar/peninsula? Could you gain some space for a mudroom from the breakfast room? Or rearrange the laundry room into some of the breakfast room space?

We recommend a round mirror like the one featured in the space found HERE. We also recommend doing a similar lighting style if you plan to use this space to get ready in the mornings. We suggest sticking with the metal tones you've already chosen for the pulls and faucet. Try switching back and forth to prevent it from leaning too much on one metal, i.e. because your faucet will be close to the mirror choose a trim that matches the pulls for the mirror.

Just some thoughts: Powder rooms can be made "L" shaped so the toilet is not what you see when the door opens. You see the side of a small wall sink in the corner you turn before seeing the toilet. A laundry room in the front isn't necessarily a bad thing. You might consider more of a laundry closet than a laundry room. You might be able to create a "mudroom" that is a hallway between house and garage with the washer and dryer facing each other at one end of that mudroom. You might be able to create a "mudroom" that is actually a hallway with a closet on one side hiding the washer and dryer and the powder room on the other set out so as the door opens between toilet and sink, the open door hides the toilet until it the door is closed.