I would also recommend looking into the Courtyard Marriott Theme Park Entrance. It's on the pricier side, but they do have suites which have a combination of beds and bunks. I stayed in the King Suite, which had a king bed in the Master and two Twin bunk beds in the second room. So it easily slept six, but it only had one bathroom. As noted, it's on the pricier side (~>$300). This hotel also has a pretty amazing swimming pool area (water park, complete with two water slides) and is within walking distance of the parks (<10 minutes).
Regarding the bathroom...the King Corner Suite I stayed in had one bathroom. You entered into the main bathroom and straight ahead was a two sink vanity. To the left was the bathtub (with shower head). To the ride was another room with the shower and toilet. So it was possible for someone to shower, while others brushed hair, teeth, etc. Still, it worked for us because half of the adults took morning showers and half took evening shower.