Vegan

re: trolley problem, realistically, I wouldn't pull any lever.

Hypothetically, if not using vaccines led to dead infants, then I would simply need to accept that, just as everyone did before vaccines were invented.

Defending one's food supply is not exploitation, but blanketing an entire landscape in poison is ill-advised for several reasons, including the danger that it poses to peaceful animals.

It would also include I’d imagine farms that say release ladybugs to control other insects since it required the exploitation of ladybugs.

That would be exploitation and therefore not vegan, correct. Sometimes it isn't possible to know which farm does what, and without knowing, every option is equivalent, and ethics doesn't come into it at all. But if one knows, for example, that Farm A exploits ladybugs, Farm B uses fish emulsion fertiliser, and Farm C sprays nicotine-based insecticide on the crop, then given only those three options, the "correct" choice in the context of veganism would be Farm C, as it does not involve exploitation. In practice, Farm C may kill orders of magnitude more animals, but all is fair in self-defence, which extends to one's food and shelter.

If you're concerned about the number of animals killed in crop production, then you should know that the most effective way to reduce it is to live vegan and grow your own food in an environment over which you have complete control. If growing your own food isn't possible, then living vegan and making informed choices about where you buy your food is the next best option, as the vast majority of animals killed in crop production are killed in the production of feed crops for cows, pigs, chickens, farmed fish, and so on.