Sounds like a great trip!
BA is fantastic loads of good leather shopping and great places to eat (if you like meat, meat and more meat!). I highly recommend a trip to the delta. It’s a day trip out of BA but its fantastic. Argentina’s version of Venice ^ ! Make sure to do the water taxi trip and don’t forget to haggle over price
Also there is a great Cuban restaurant down by the docks in BA which is a must (Cant remember the name right now)

Iguaçu is amazing! Pay the extra for water fall views at the Sheraton and don’t forget to pack a good rain coat! Make sure you take the trip down the river and under the falls.

I had 6 days in BA could of had another 2 years! and 2 days in Iguacu may another 1 or to would have been great but not much more.

I wish I could go back today! I am planning another trip to Argentina in 2 years