I would not have the feed and tack by a toilet or wash rack, I would have wide aisle ways , if you had to get a tractor in for any work, adding soil etc,then you need to have some room to manuever. I would have hay stored away from the stalls. I would have a larger tack shed.
You may want a larger feed room to store baled shavings , blankets take a lot of room, also are you renting out stalls ? Doing a shared tack shed ? If not shared, then I would make some smaller tack rooms toward the back.