You want to primarily ask about behaviour when you interview your stakeholders.
Personas in UX are usually focused on behavioural characteristics, or attributes/contexts that directly impact behaviour, and sometimes attributes that imply in a stereotypical manner (eg. retirement age implies accessibility issues, moms with young children are time poor).
Ask questions like:
- Are there some users that are more persistent than others, are there some users that give up early?
- What proportion (if any) of your user base appear to bring extensive experience/knowledge/understanding from elsewhere?
- Is it typical that users explore the optional parts of the interface/site before deciding on an action? Are there some users that instead make a bee-line for what they want and ignore any possible distractions?
- What kind of users are more spontaneous than others? Are there groups that are more conservative/careful/risk-averse than others?
NB: don't ask "Are users persistent?" and other forms which treat all users as a cohesive block - you are trying to identify multiple personas, not settle on some generalisation of all users.
It helps if you first make a list of behavioural dimensions which are relevant for you project. Spontaneity and risk-aversion are relevant for a stock-trading portal, not so much for a health-plan selection website.
Then for each of the primary questions you can expand and drill deeper asking about the user's context or attributes.
- Tell me more about persistent users ...
- Which customers are typically more likely in that group [of persistence]?
This gets easier as the stakeholders would likely be volunteering this information in answering the primary questions (e.g. "Yes, students are more persistent").
If stakeholders can speak to secondary characteristics (age, ESL, occupation, etc ), being informed by client records (etc) cross-referenced to website analytics, then that is quite useful.
However, they often can't actually accurately speak to secondary characteristics but they would likely nonetheless do so, revealing the stereotypes they believe. This isn't a total wash though, as personas play the role of stereotypes and you'll be picking up some colour which matches their expectations.