Does the data-dump contain all votes cast by people, or only those close votes that are displayed (i.e. votes on posts that got enough votes to close)?
Close votes are not part of the data dump. Questions that are closed are part of the data dump, with an indicator (the timestamp in the
ClosedDate column), however that is the only information provided.
To see the table and columns that make up the data dump tables, you can look at the information provided when creating a query on SEDE: http://odata.stackexchange.com/stackoverflow/query/new