Thanks for the replies bosman and deant!
We figure that lodging will be the hardest and most expensive. It's good to know that there'll be options (like the floating hotel) should our reservations fall through.
As for the flights, I was just hoping to redeem points to reduce the cost of my flights (we're also going to Peru or Argentina before or after). I'm not a whiz like the rest of you are at travel hacking so I'm not expecting to use points to get an entire flight to Rio free or get bumped up to first class but I was hoping to use whatever points I accumulate to reduce some of the flights by a few hundred dollars.
Anyway, thanks for you inputs again!