1:15 isn't enough for the I->D connection at SCL. Even though things seem to be working quicker at SCL in the morning it's till to tight.

A 1:50 connection at the end of the trip sounds reasonable assuming you can check your bags through. Will probably depend on the agent at PUQ.

Having said that, aren't there several flights to PUQ each day? Furthermore, flying domestic is a breeze, and the trip to the airport isn't bad at SCL, so I don't see a huge benefit of scheduling your PUQ trip at either the beginning or the end.