thanks mrgom - appreciate the data points. Your data points along with JohnnyColombia's were very helpful - I'll stress less on future planning on South America trips
I ended up doing the alternate itinerary - Bogota, Medellin and Lima. Nice side effect of the alternate itinerary was getting a redeye flight to Bogota from Houston, and redeye flight back to the US from Lima, as well as adding Medellin to the itinerary using United miles and paying for a one-way ticket between Bogota and Medellin. So less time in transit and no connections with all nonstop flights..
My original "perfect" itinerary was using AA miles but with stopovers in Miami both directions and daytime flight to Lima from Miami (landing in Lima close to midnight), as well as a long layover in Miami on the way back from Bogota, along with using BA miles for Lima to Bogota. So it ended up working out, but deep down I wanted to check out the Centurion lounge in Miami, and check out the Corona Beach House with Priority Pass - lol. I'll have to settle for nonstop flights from Houston instead but at least Houston has a Centurion lounge.