It appears from the MediaWiki API:Query page that you can only resolve a redirect one at a time.
The document even says "The example below isn't really useful because it doesn't use any query modules, but shows how the redirects parameter works."
But how can you get the redirect information -- using a query module that does return multiple results?
If you have any result that returns page
s, then you can just append redirects
to the query and it resolves the redirects. If you don't have results that returns page
s, you can usually convert it to that by using a generator.
For example, the query
returns something like (shortened)
<api>
<query>
<categorymembers>
<cm pageid="648" ns="0" title="Actress" />
<cm pageid="19887132" ns="0" title="Administratrix" />
</categorymembers>
</query>
</api>
If you convert that into a generator
you get
<api>
<query>
<pages>
<page pageid="648" ns="0" title="Actress" />
<page pageid="19887132" ns="0" title="Administratrix" />
</pages>
</query>
</api>
And if you now add redirects
you get
<api>
<query>
<redirects>
<r from="Actress" to="Actor" />
<r from="Administratrix" to="Administrator (law)" />
</redirects>
<pages>
<page pageid="21504235" ns="0" title="Actor" />
<page pageid="6676496" ns="0" title="Administrator (law)" />
</pages>
</query>
</api>