XQuery 3 support in MarkLogic might help with this, but otherwise no. You can put the cts:query part in $query like this though:
let $query := cts:and-query((
cts:element-attribute-word-query(
xs:QName("para"),
xs:QName("role"),
"intro") ,
cts:element-attribute-word-query(
xs:QName("title"),
xs:QName("role"),
"inline")
))
let $number-of-results := xdmp:estimate(cts:search(doc(), $query))
let $results := cts:search(doc(), $query)
return $number-of-results
HTH!