Hi and welcome!
As long as you have a non-rev listing for your return flight, you are good to go. These places do not need a confirmed (revenue) flight back. Based on loads, you can always make changes to your listing. I was only asked once about return travel plans. I was nonrevving to AUA on DL one way and AA on the way back and the DL agent asked about my return travel plans. I explained I was nonrevving on AA back and provided a PNR and that was sufficient. I've been to all but Colombia of the places you are interested in (although I've heard great things about Cartagena) and immigration at these places never asked about return travel plans. I have been places without creating a return listing since I didn't know when I was going to return and it's not been a problem.
Bookmarks