So near the end of act 1, the group faces off with the "pirate queen". At the bottom of page 35 it says that in addition to the queen, you have two sorority pirates per PC, and it refers back to the minion listed on page 31. On page 36, after the stat block for the "Pirate queen", they have stats for "queensguard", a much tougher minion to face down, and armed completely differently than the normal pirates.

I'm not seeing where queensguard are mentioned in the book beyond this stat block, and their flavor text shows that they are guarding who they believe to be the true pirate queen. Should she instead be guarded by these, instead of the standard sorority pirates?

I'd say go with both. Set up the queens guard the same as the pirate group for the fight, have the pirates rush in for close combat, while the queens guard hangs back and provides initial fire support. Once the normal pirates are down or incapacitated, then the queens guard wades into combat. Hey, its a climactic scene so pull out all the stops, right?

Makes sense, though it doesn't say how many queens guard there are.

I would use the same number of queens guard as the regular pirates.

I remeber there being a minion or rival profile that you have to refer back to the Core RB to find? Could be wrong but LugWrench gave the best answer.