Is there a way to tell by clicking on a planet if it has a population or not? I launched 2 colony drones from 1 and 2 hexes away, and they should have landed (unless I managed to launch them before the colony drone bug was fixed). However, when I click on the planet I don't see anything about a colony, and the drones themselves are no longer on the map.

All you can do at the moment is use space to view last turn and then click on the drone - the description shown on the drones turn report will tell you what happened.

Clicking on the colony will eventually also tell you, but not at the moment.