Yes, I think that grammatically, "persons" and "people" are interchangeable in the plural terms "persons with disabilities" and "people with disabilities." In actual usage, however, the term "persons with disabilities" has more flexibility because it can be rendered in either the singular "a person with disability" or the collective plural "persons with disabilities." In contrast, "people with disabilities" will always be collective in sense because, well, the noun "people" is a collective plural.
Another consideration is that as a rule, the nature of a person's disability is unique to that particular person, so I think it's more precise and prudent to refer to him or her as "a person with disability" rather than classify him or her under the generic plural term "people with disabilities" that may, in fact, be comprised by persons with many different kinds of disabilities. For this other reason, I think that using the term "persons with disabilities" for the collective plural and "a person with disability" for the singular is the better option from a semantic standpoint.
