Interesting plural -I thought it might be 'echtgenoten' - is there any rule to help?
'Echtgenoten' is a correct plural too, but for the male counterpart. 'Echtgenotes' is the plural form of 'echtgenote' (which means wife) and 'echtgenoten' is the plural form of 'echtgenoot', which could be both 'husband' or 'wife' (but 'husband' is a more common translation).
Thus - if I assume correctly - 'echtgenoten' could be 'spouses', and 'Wat doen die echtgenoten?' could also mean 'What are those spouses doing?' in the sense of 'What is that couple doing?'.
"deze" is "these" (although it apparently is more complex) which means your sentence is "what are these wives doing" which you should agree is not the same.
isn't these and those based on location to you? These would be closer to you, and those further away?