Great to know that you and Jill will be with us. I know what you mean about being ready to be in Brasil in November. My wife thinks that today's 90F degree heat and 85% humidity is wonderful. Then she is freezing at 60F. In 23 years of marriage the only real thing we argue about is the setting on the thermostat.
My Sister-In-Law called today with more information about Itajai and if we don't do an Iguacu tour we may just take in the beaches, the outer valley, the city and nearby Blumanau and Brusque. It also looks like Porto Belo is nearby but you would need a ferry to get there. So even if you don't do Iguacu there should be plenty to do.