Hah!! Yes, I too was raised on the GuernEEville pronunciation. And also "The Irish Sporting Green" reference. (When I was a kid, I actually thought it was about Irish sports!) Sorry, but I do not know the origins of either.
My family home was on 19th and Quintara. My Dad made up a fanciful tale about how the street was named after us - the Quinn family. And, that the "tara" part was in reference to Tara, which was the inauguration place and seat of the High Kings of Ireland...thus implying that we were descended from Irish kings. It wasn't until I was in high school that I learned that Tara was, indeed, the mythological seat of Irish Kings, but the rest was not true. Thank goodness, while in grade school, I had not run around the neighborhood, bragging about the Quinns descending from royalty!! Regardless, I still appreciated my Dad's whimsical sense of humor.
In truth, it is believed that the street name was thought up by the Parkside Realty Company, which developed the Parkside area, because the developers liked the way it sounded!!