I wasn't quite sure what to expect from Brunner when he entered his freshman year, although he was a top 50 player when final rankings came out, I believe. With Horner, though, I personally felt like we would get out of him what we did his freshman year. I was not surprised in the least.
He had been around the block on the AAU circuit against national competition as the floor general (a difference from Bru, who was also on that team and played quite well) of a very good AAU team. Based upon what guys like Horner would typically do in that environment there was a reasonable expectation of his freshman year.
I believe the same can be extrapolated for Gesell, within reason. I believe his statistics will be slightly better than Horner's as a frosh, and his impact at least as good.
I am not quite so sure about Woodbury. Per Jon's comments above, I think he is a little bit more of an uncertainty. That being said, I will go out on a limb and say I am not sure why a reasonable expectation from him wouldn't be seven points and five rebounds at minimum, as well as a significant impact on defense.