If stakeholders resist in sharing information is because we have not done a proper identification, engagement and follow up of them. Stakeholders should be mapped based on their capacity to influence the project, and their attitude towards the project.
My recommendation is to follow the HCMBOK mapping criteria, where based on capacity to influence, there are the following categories of stakeholders (Decision maker, Direct influencing agents, Opinion makers, Spectators), and based on their attitude the following ones (Sellers, Unstable, Probable resistant, Open Boycotters, Veiled Boycotters). Depending on how is categorized each of the stakeholders based on those two parameters, we have to follow an specific strategy with them, that will not end just on the identification and initial engagement phase, if not that it will have to be followed up and reviewed during the whole project lifecycle to assure the project success.