\parameters(person1, person2, person3)

\procedure person-statement(person, slot)
  <<person>> says:

  <blockquote>
    <$slot $name=<<slot>> $depth="2"/>
  </blockquote>
\end

<$transclude $variable="person-statement" person=<<person1>> slot="statement1"/>
<$transclude $variable="person-statement" person=<<person2>> slot="statement2"/>
<$transclude $variable="person-statement" person=<<person3>> slot="statement3"/>

Note the need for the $depth parameter to get the value of the slot since there is an intervening transclusion (of a procedure).

Here's a test with two people/statements:

Our team has a little bit of extra time this quarter; what should we use it for?

<$transclude $tiddler="Statement" person1="Alice" person2="Bob">
  <$fill $name="statement1">
    There are not enough croissants available in the cafeteria this week. We must create a committee to solve it immediately.
  </$fill>
  <$fill $name="statement2">
    Personally, I would prefer that our next initiative involve AI. We don't currently have enough buzzwords on our organization's homepage.
  </$fill>
</$transclude>