Jhin being a Virtuoso and the 4 Champions
Is there a play on words on that Virtuoso thing? His mask resembles angelic and archaic for some reason and the first thing that came in mind are possibly his title is a play on words which brings up the 4 Cardinal Virtues - Prudence, Justice, Temperance and Courage. These 4 Virtues seems to fit perfectly well on the 4 champions that were shot on the teasers.
Zed - plays on Prudence - Wisdom, Insight and Knowledge. Basically these things stemming as the head of the Shadow of the Order, teaching others in the ways of the Shadow. In the teaser, branches grow out of his head/eyes, showing his growth as more of a teacher.
Sona - plays on Justice - A person with a perfect balance of Selfishness and Selflessness. Her music being played for all those to hear (Selflessness), they can disregard Sona herself as someone without a voice (Selfishness). What would be an audience reaction if one were to hear her voice? Would they choose to hear her words or her instrument instead? In the teaser, smoke comes out of her mouth symbolizing how empty her words are while her throat flashes with butterflies flying away, showing the beauty yet out of reach.
Vi - plays on Temperance - Voluntary self-restraint. Quite an identity and impact for Vi herself, joining the forces alongside Caitlyn to take control of her actions. Her teaser reveals her hands on fire, her hextech gauntlets breaking off, showing her ability of restraint and possibly giving up on her rash attitude.
Garen - plays on Courage, a choice to confront pain and danger. A fitting for the person like Garen and his role to Demacia. His teaser appears as crystals breaking off, with each action he is required to use his courage, his slowly crumbling but like a crystal, its enduring and strong, it might chip away but he's still whole.