This is great. I've been thinking about doing something similar with cartoon characters to build a Disney-style companion for my son as he gets older. I'm imagining something like an Alexa assistant but with Mickey Mouse's voice.
I know caselaw isn't settled at all on all this but I'd absolutely avoid posting anything on the web mentioning D' and the black and white mouse again unless you are interested in finding out firsthand how the law gets settled here ;o).
The hardest part of this is in dataset creation. It's hard to clean and annotate the data and can be quite manual. That's why companies with lots of data will win.
There are automated techniques to help with segmentation, bandpass filtering, transcriptions, etc., but they're far from perfect.