I'm confident that the First Name of the newspaper person you are referring to is George. He did live in Austin and was the person involved with the newspaper there.This is also why that someone, many years after 1840, may assume the mount was named for him...
We'd like to find documentation at the time (1830's-1840's) referring to the name of the mount. As mentioned on the www.kbsb.com/reward site, George himself wrote a book, published in 1840, and referred to "Mount Bonnell", but he did not say it was named for himself... even though he did mention other landmarks and gave the person the landmark was named for, when he knew that information.
I will look into the leads you provided - and yes, the reward is serious.
Again, thank you. And please mention more if you come across anything else!