Travelling in southern brazil and going to peru

1. Its probably better to go Rio - CG - Foz. As there is one direct flight from Foz to Lima per day. Though expensive, it may be cheaper to go from CG. Check both, and see whats cheapest. Apart from that, maybe try Santa Cruz (Bolivia) as they will probably have cheaper flights but its a good trek from CG to get to. You need to weigh up if thats worth it or not.

2. Yes. There will be taxis waiting for you when you leave. Not sure about buses.

3. Do the falls when your in Foz from both sides. Go the Brasil side first, then head to the Arg side. That'll save time when you go back. Its a long bus ride to BA.

4. Flight back to Sao Paulo. Flight from Sao Paulo to Lima. Or Rio.

2- There are buses until about 24:00 - 1:00 that leave from the airport to both the falls and downtown Iguazu. The stop is right beneath the last taxi at the airport's taxi stand (taxi's are there 24/7, costing about 45R$ to get downtown).The bus is about 3R$ and I remember being able to get anywhere downtown from where the bus would take you. The is a scheduled at the stop which shows the hours the bus leaves, and in my case, it was fairly accurate. If you get out of the airport fairly quick, you should be fine.

3- I only saw the Brazilian side of the falls, but I was very happy with it. Do the little trail with the small causeway into the middle of the falls. Avoid the silly boat rides into the falls, they are as adrenaline rushing as they claim to be but at 15 minutes long and 170$R I found it a rip-off. I was happy paying for the park and what was included in it. Can't speak for the Argentine side, but I do give the Brazil side the thumbs up, and worth the day you'll spend there.

To get the full experience, seeing it from both sides is well worth it. If you are not heading further into Argentina and need a visa or pay the reciprocity fee than it may not be worth it.