Apprecciate all the comments. Will get to GIG TAM check-in with plenty of time to inquire abour my options, if any.
I was 67% sure I was returning to GRU from CGR, with return from Sao Paulo being the second option. Really surprised to be returning from GIG, but hey, RIO is my favorite city, so even with my long wait for flights, I'm still happy about this.
Willl post about my luggage experience in a couple weeks. I also have a return trip to Brazil later this year, and again will have a definite date on which I want to leave Brazil (probablu GRU again), but no confirmed idea as to where I will be! Kinda exciting, but it does lead to wasted time, like I have on this return.
Your dediction to Flyertalk is admirable: making multiple trips to Rio in order to conduct research on luggage transfer, etc. We're in Brazil and know the hardship you're undergoing.