The purpose of the First Posts review queue is to help new users get up to speed by giving them feedback if needed. All the queue does is identify new users' initial posts in an easy to find place to facilitate feedback. It and the Late Answers review queue don't add any extra options relating to closure or deletion because those posts are not in those review queues on the assumption that they have a problem. So in that sense, it is like finding the post anywhere.
In general, there's no obligation to leave comments when flagging or voting on closure or deletion, regardless of where you do it from. So if you come across a post anywhere on the site with serious issues, you can elect to flag it (or vote on closure/deletion if you have sufficient rep), and choose whether to leave a comment as well (flagging doesn't provide any advice to the poster).
However, if you are in the First Posts queue, it kind of defeats the purpose if there are serious issues and you don't leave feedback. You might choose not to leave a comment to the poster when you flag or vote on closure or deletion. But in the First Posts queue, the reason for being there is to provide needed feedback to the new member, which is separate from recommending moderation action for the post.