Full news item: https://worldoftanks.eu/en/news/specials/eggstravaganza-special-april22/

My mission guesses from the hints:

1: Passive scouting/spotting from cover? (do a certain amount)

2: Fire seems like the obvious choice, but could be too simple. (Cause a fire)

3: ‘Splash’, so HE shells (do damage with etc.)

4: Kill an arty, screenshot it 😂