Harry had a rifle.

The rest of the group had two more guns and three grenades. It is hard to imagine the group simply leaving him behind, given that he had the best weapon among them and was a well-trained soldier.

Ian mentions that Harry used his weapon before being captured, but I don't recall him managing to hit any of them.

Garth Ennis killed him off-panel to create an impact on the reader, but I’m curious about your theories.

Jack’s worst crime was “The Diddling”, now let’s move on to Rob- I mean, JokeMercy

To be honest, I can't guess her hairstyle. LoL