I doubt you have much to worry about. While the plastic melted and possibly released some volatiles, the rest were vented. It is possible that some deposited on the walls of the oven. Any such deposits will either stay put in the future and do no harm, or come off the walls and be vented out of the oven. The concentrations are small and there is a principle medicine & environmental science that the "poison is in the dose" (e.g., all of our food has trace levels of poisonous insecticides on it, but it doesn't kill us because the levels are relatively small.)
To be safe, I'd wash the walls with a dilute solution of dish detergent followed by a dilute solution of vinegar water / baking soda water to remove whatever did deposit on the walls of the oven.
Even if you plastic containers don't melt, they have the potential to release volatile chemicals. A safer way to microwave is to always use glass or paper containers. Going forward, if you're concerned about the volatiles that deposited on your microwave oven, you can heat food in covered glass container (NOT sealed like a jar!). I heat my oatmeal bowl with a small plate laid over the top of the bowl to stop boiling over.
If you're going to throw it away, let me know where to pick it up and I'll come get it... I'm sure the microwave oven is fine!
