As you've said, Premium and Premium Plus cabins do not have a bath, whereas Standard Cabins do. I found this which says that all standard cabins have now been updated to have the same facilities as the premium cabins. It states that they have shower rooms, so I would assume that they no longer have the baths, as you fear? Might be worth contacting them to double check.
For arrivals from the 1st April 2015 the standard cabins will be updated to have the same facilities as the premium cabins and be re-named Trapper and Pioneer, the difference between the Trapper and Pioneer cabins will be their proximity to the village, the Premium Plus cabin will remain as they are currently.
Trapper Cabins
Sleep up to 6 people with one double bedroom and a second bedroom with 4 single beds, 2 shower rooms, air conditioning and International television channels
Kitchenette equipped with microwave, dishwasher and hot plate
Beds made up ready for your arrivals
Towels provided
Outdoor patio deck with picnic table and BBQ, private parking next to your cabin
These cabins offer extra peace and quiet
Pioneer Cabins
Sleep up to 6 people with one double bedroom and a second bedroom with 4 single beds, 2 shower rooms, air conditioning and International television channels
Kitchenette equipped with microwave, dishwasher and hot plate
Beds made up ready for your arrivals
Towels provided
Outdoor patio deck with picnic table and BBQ, private parking next to your cabin
These cabins are closer to all the facilities at Disney's Davy Crockett Ranch
