I had a patch put in my old all seasons a couple years ago, basically right in the corner of the tire. I actually asked the local tire shop if they could put a patch there giving them an opening to sell a tire, but they said it would be fine, and it was. No leaks and I recently had these tires taken off and the patch was well stuck with no signs of movement.
That was on a set of high profile 3 seasons that rarely got stressed in cornering, but had lots of sidewall movement as they were single ply sidewalls. I guess the tire in question should have much less sidewall deflection due to a stiffer sidewall.
With the small hole being 2.5" away from the edge I bet a tire shop will patch it without a question. Yes it probably does raise the chance of tire failure some tiny amount, but if I got a similar hole in my new BFG comp2 I'd patch it and motor on.