i would include everything just to be on the safe side, or they MAY think you're trying to hide your household income for some reason and it may eb delayed?? now this is only my opinion, im sure someone will correct me if im wrong
as long as you show you full household income and full expenditure then you should be fine and answering your question about your wifes DLA, i wouldnt of thought they would take this into account when looking at your available surplus??
again, if im wrong someone will correct me but hope this helps

i went through this myself, but only had myself to include on the income and expenditure, but i think being completly upfront about your finances is only a good thing in this situation, it will save any delays in your application.
hope this helps and good luck