Sam2, according to the pri megadim bishul basar bechalav is even by roasting (check his hakdama to basar bechalav). Pizza can be considered a kli rishon as it’s a davar gush. In practice, most food we throw out isn’t hot enough to be an issue, but it’s something to be aware of. Bishul basar bechalav even without intention to eat is a major problem with biofuels from recycled restaurant oils.
As for the lard in oil roommate,
befeirush in shulchan aruch- it’s assur for the person who did it bemeizid and the person for whom he did it. He did it for you. I’m avoiding the issue if a drop is avidi letaamah and therefore not batul be’elef, as there are many who say similar tastes can’t be avidi letaamah.
As for the oil, it’s based on “steam jackets”- pipes filled with water vapor of a product used to heat another product. Factories use them all the time to save heating costs. In this case, the same factory made lard, and the pipes were filled with water vapor from lard, making the pipes treif and therefore the product they were heating treif. No water vapor gets in the product, product is pure canola oil, and still treif. Steam jackets are one of the most common kashrus problems in factories and hotels.
3 large pieces of steak, 1 is treif. When would we allow this despite chaticha harauya lehiskabed?
Bonus basar bechalav issue- it is assur to be mevatel issur lechatchila. basar and chalav are kosher until treif. Can you purposely dilute 1 part milk in 61 parts water, and then use that water with meat?