I think it sounds like a good plan to start out.
The real hard part here is that your wife is of the mind that she has to do "3 meals." reality, she can do one meal.
Soup and Salad is easy. These days, we have *two* crock-pots going starting at noon (i even put them on timers to turn on themselves). One holds the chicken, roast, or what have you, which is on low for 4 hours). The second has whatever soup i'm making. I put all the ingredients in the pot, add the stock, and walk away. Literally, walk out of the house at 8 am. The timers turn the crock pots on at 12 and 2 respectively.
DH gets home around 4. Chicken is done, so he turns the pot to "keep warm" and the soup is done so he turns that to "keep warm." And hen he puts together a salad.
Then he serves DS at 5 pm (if I'm there, we all have dinner around 5:30) and then he and I have dinner at 8 when DS goes to sleep and I'm home (when I work evenings).
Honestly, it's *one meal* it just has three components. And if she likes breads/grains, whatever, she can still make those -- in the crock pot or oven even -- and voila! she has something she can eat for several days too.
I suppose, though, that sometimes people don't want to relearn the methods that work for them, so I don't blame her.