Morphs are just that, pokemorphs. They breed true. Opinion of them depends on the town. some like them, some don't. Overall the radiation is slow to work, can take up to a week of exposure before lock. Unless you're practically hugging the generator, then not only is it faster but can go full poke. Morphs don't get affected by the radiation anymore. That may seem like morphs are perfect diggers- except they’re recognized as Pokemon to a lot of systems now, including security. So a lot of secured areas wont let them in.
Appearances of Morphs can vary between about 25% and 75% Pokemon, but they all have 2 common physical features. First, their eyes have something different about them from normal human eyes- whether eye color, pupil shape, or something else, there is something visibly not-human about them. And second, they completely lack any sort of fingerprints- either smooth skin, pads, scales, or some other kind of skin would replace where they'd be on a human. These both cause issues for Diggers trying to get through the surviving biometric security in Center ruins, as they'll recognize those as 'not human' and bar entry.