The harvest seems like it's unfinished to me. Personally I would go with the antique white finish. Kids or no kids, all cabinets get dirty. And being they are a white finish, you'll wipe them down a lot more than if they were darker as you'll see the dirt. You're laundry room will just be cleaner than :)

I would move the laundry tub to the right, filling that 5” gap. I would add a wall and a door to the toilet area because people are uncomfortable using a toilet in an open multipurpose room. If budget is tight right now, I would still plan to make the toilet private in the future and that 5” space will be needed for 2 x 4’s and drywall on each side. I like your idea of using the space between the washer and dryer for hanging space. I use mine to hang clothes as they come out of the fryer and also for those delicate things that don’t go into the dryer. I had a built in water heater as you are suggesting. We built a cabinet above it, probably 24 x 24 or whatever is the same size as the water heater. It had such useful storage, going to the ceiling and having an adjustable shelf. Be certain to leave room to remove the water heater when it needs to be replaced. Get adjustable shelves for your two 30” cabinets over the washer and the dryer to give you flexibility in what you store there. It was useful for flower vases, light bulbs, extra paper towels,, in addition to Tide, Downey, and all my other cleaners.

We have Ikea cabinets in our utility room which has our laundry and hot water heater. We also used their laminate countertops--no pictures since I'm at work, but they've held up without any issues for the past 16 years. I make soap, start my seeds, etc. down there and those counters have seen some action. If you drop anything heavy., it'll dent enough that you'll see the wood material below but it would require some force. I'd go with something very interesting in the room, either a cabinet color or floor tile that will make you happy every time you see it.

We need pictures.