The Door is probably the most general of all the texts and you can apply it to anything involving change.. if you do some research on Holub and the context in which he was writing his poetry you may be able to make some points about how war affects peoples' lives.
You can use The Door wrt Peter, Feliks OR Peter's mother (Ka.. something something, I forget her name). Or even Chronic Ward, although I'd stay away from that one if I was you. Observe how people's reactions to change or the possibility of change contrast, for example. You can compare poetic techniques and the different methods by which the two composers achieve their purposes.. or something like that.
However it's probably not good to use The Door since it's also a poetry text... use one of the other texts instead (variety of medium).
Note also that you won't be asked to refer to ALL the poems.. and you shouldn't even if they don't specify how many you should study. It's better to go into a few in a lot of detail than many with only some detail.
And order doesn't really matter - perhaps you might want to mention the dates that they were written and reflect on how the author's perspective may have changed over time.. but since the poems aren't really chronologically linked in the syllabus it's probably not too relevant.