Regarding cherry. I've made beers with whole black Cherries, Oregon Fruit cherry puree, and most recently with Fastfruit tart cherry concentrate. Of the 3, cherry puree contributed almost no cherry flavor at 20lbs in a 6 gallon batch. The whole dark Cherries gave a hint of bing cherry in a quad. That was about 6 pounds in 6 gallons. The cherry concentrate, 1/2 gallon in 6 gallons, dominates the beer. That was in a roselare beer.
So, if i want dominant cherry flavor I'll be using Fastfruit concentrate in the future. Maybe not so much next time, maybe same amount cuz I kind of like it that way.
In your beer, I would brew it to have a high residual sugar, high finishing gravity, if you want sweetness. Then use a type of fruit (whole, puree, or concentrate) and amount that will impart the cherry flavor you want. Let it ferment out properly, and get the residual sweetness from the base beer. This would result in a safe beer and probably same effect as going with chemistry or pasteurization.