It's only 12 events. They can't possibly run that late at night. How noisy are they for the residents of St Nicholas and San Marco (they may well be noisy for the people on the river - I have no idea)? And although they may be noisy during the hours of the events, is the language used really an issue?
What's the point in having Metro Park if we can't have ticketed events there, really? It's only 12 events. I don't know what the rules are, but I'd hope there are limits to how late the events can run in order to ensure the residents across the river aren't kept up at night. If not, that seems like a more reasonable solution.