Slide a popsicle stick in each half, about halfway through, and then freeze them for a few hours (covered).
Chocolate coating
Make the chocolate coating by melting all the ingredients for that coating in a bowl over hot water (a bain-marie).
Let the coating cool for a bit and then dip each banana in the coating, swirling it around to coat it evenly.
Optionally, dip the coated banana in chopped nuts and then place it on parchment paper (or other non-stick surface) in the freezer for at least 5 minutes (and store in the freezer, covered).
Vanilla coating
Combine all the ingredients except the coconut oil, into a high-speed blender and blend until creamy and there is no trace of nuts (it can take a few minutes).
Add the resulting cashew cream to a bowl and place it over hot, simmering water.
Add the coconut oil, and stir until completely melted.
Cool for a bit and dip the bananas in it before freezing them again for at least 5 minutes. Store in the freezer, covered.