I would say that we use "bring life to something" when that something is primarily in the realm of ideas, totally dependent on humans to apply it to our lives. That something is inherently dead.
- In Example 1, instruction is inherently lifeless, a bunch of words, totally dependent on humans to make it a part of our lives
But we use "bring something to life" primarily when that something has potential of life, so our role is merely assisting to develop that potential to be realized. Although strictly speaking a story, a language, or a character in a story are inherently dead, they can be in this category too since they mimic something living in our world, if in the sentence we want to highlight their living potential.
In Example 2, cruelty is a human potential; the two young men could have manifested their cruelty on their own. "brought to life" here refers to our assistance to manifest that cruelty in our own reality, but our assistance is NOT strictly needed for them to manifest their cruelty somewhere else.
In Example 3, French refers to a living language used by many French speakers outside the "French as a second language" classroom. The teacher is merely assisting the students to participate in something already living. Life flows FROM the living usage of French TO the students. Contrast with Latin, a language that has been practically dead for centuries, reduced to the realm of ideas, since there is no more native speaker of that language. "The community brings life to the Latin language by using it as their primary language." highlights the deadness of the Latin language. In this sentence we can substitute Latin with an artificial language like "Klingon". Life flows TO the dead language FROM the community.
Other example: "Victor Frankenstein then proceeds to bring to life his monstrous creation." vs. "Victor Frankenstein then proceeds to bring life to his monstrous creation." The former sentence highlights the creation's potential (the sentence implying that Victor resurrected a corpse) but the more powerful second sentence highlights the artificiality of the creation (thought by many to be a patchwork of stitched-together parts of several corpses) thus totally dependent on Victor to infuse it with life.