Every time I have been to a Disney buffet, I have seen something really unacceptable.
People coughing or sneezing in the direct proximity of food without covering their mouths.
Unsupervised children running around, grabbing stuff with their hands - bread, pizza, etc.
Picking through dessert choices such as cupcakes with bare hands and putting back the ones they deem unacceptable.
Returning to the buffet with a pre-used plate covered in various food and sauce residue and leftover scraps and then using tongs to scoop new food onto the dirty plate, the tongs making clear contact with their dirty plate.
I once saw an idiot scoop fresh fries onto their pre-used plate that was covered in ketchup. The tongs were covered in her ketchup when she put them back.
So no. Buffets are not going to work out well anytime soon under the current and ongoing pandemic.