The form of a persona depends on it's usage. Decide how it will be used in further development process to gather more requirements about what you need to ask. For example sometimes it happens that one gets the most active feedback from users that do not play the primary nor the secondary role - so it wise to ask about the excluded personas.
Next, one needs to know what personas should be included and what are they. First interviews are for stating and establishing the hypothesis, the next ones for deepening the personas.
Another thing, one should create the personas around the common goals and roles, not around common attributes. If a system have a multiple user groups, each having a common goal and each consisting of people of different age, gender and disabilities - then maybe that whole system need to be designed for different ages, genders and disabilities in mind. The personas are there for helping you help users achieving their goal.
Persona is a basement for scenarios. Of course, mistakenly created personas may lead the project off track, but remember - personas are only hypotheses. The worst is a lack of user feedback in the later stages. If one doesn't know the flow of actions that user performs to achieve goals (scenarios) and if one doesn't test prototypes against users, then one takes all the investments in a project into a roulette. Surprise is at the end.
If you plan to arrange the user needs with the Kano model you will surely find that user can usually speak about some performance issues. She will have a hard time telling you about all the basic needs, because it's "so obvious". She will tell you nothing about the excitements she doesn't know (and she isn't so creative to think of). So recognizing the basics (with use of scenarios) and creating "the wow" is your part.
In my opinion the lack of user research on personas isn't so risky. If your stakeholders have a frequent contact with users they can a very fairly describe an overall picture. Nevertheless, without further user involvement every persona will be only a insignificant artefact.