The minimum needed would be a soap dispenser for each sink, paper and/or cloth hand towels and Kleenex. Additional items to consider are hand sanitizer and hand lotion. Sinks below counter top reduce water splashing, as do auto-faucets and auto-soap dispensers but they can be annoying. Drop holes in counter top helps maintain cleanliness. A shelf over the sinks keeps items off the counter helping them to not get wet. Windows in public restrooms provide fresh air, although not always possible so exhaust vents are necessary.