Hi Nick. You are correct in your observation about no playback on a record armed audio track with punch-in/out set. As soon as an audio track is record armed, its playback is muted, regardless of whether a punch range has been set. I may change this behavior in the future.
As a workaround you could work with two tracks within a group track, where one track is record armed with the audio input assigned, and the other is purely a playback track. When you have recorded something on the record armed track you want to keep and preview on your next punch-in/out take, you can drag the sound event to the playback track.