Help me plan my South America Trip

My family (7, 9, 11 year old) and I will be landing in Sao Paulo early in Jan and departing Sao Paulo early in Feb.

We have been on very short trips to Rio, Iguacu, Buenos Aires, Peru (Machu Pichu) & Chile (Santiago, Easter Island, Punta Arenas). Don't mind repeating.

I know we will have to backtrack at some point.

Wanted to definitely go to the Galapagos and the Amazon (open to any country). However, hitting many countries might be interesting (i.e. Uruguay, Paraguay, Bolivia, Colombia, Venezuela, feel free to add/or subtract etc.).

My problem is the lack of direct flights between countries.

I was hoping someone with local knowledge could 'connect the dots' most efficiently.

Any advice on how to efficiently purchase the South American segments efficiently would be appreciated.

Thanks!