Regarding the accomodations:
-All of our accomodations were great.
-We gave Isabel a rough outline of where we wanted to go and what we wanted to see, and also a rough guideline of about how much we wanted to pay for accomodations.
-She came back with her suggestions, revising a little bit the order that we were going to do things, and helping us to determine how long to stay in each place. She gave us three choices for accomodations (in our price range) for each spot (and usually her top choice). We then reviewed each of the accomodations (looking at their web sites and the reviews on Trip Advisor), and made our choices.
-The first place we stayed in Buenos Aires, the Trianon Recoleta, was a suite with two full baths and three bedrooms. This was great for the four of us and may be also good for your family group.
-In Iguazu, she originally had us staying the first night at the less expensive St. George (after our evening arrival) and then transferring to the Sheraton the next day for one night...this was to save us some money (we changed this when our schedule was altered by a cancelled flight).