"sort" option in query does not include results that have no value in sorted field

Well, if you do not query for a property you cannot sort by it since your printout statement cannot be fulfilled. Somehow you have to pick up the date from the pages/subobjects with the query. See sorting results. So your query should be

{{#ask:[[Category:Market research]]
|?ResearchStatus
|?ResearchType
|?Description
|?BeginDate
|sort=BeginDate
}}

[[kgh]] (talk)

This is about sort statements that filter out the rows in which the sorted field is null, I think. An old and already reported problem of SMW.

Alexander Mashin^talk