I think Vonleh's issue was attitude, iirc. I'm pretty sure I read somewhere that in his draft workouts something came across bad to Danny or Brad about his attitude. The kid has talent and potential, but with the culture that Brad is trying to build here I think they're trying to sway away from those types.
Now I'm of the opinion that the package was too much, but you HAVE to think that Danny said "Hey, I have Olynyk over here. Since Kamibsky is a clone of KO, why not substitute him for one of the picks?" If they were set on Kaminsky and we're working under the assumption that KO and Kamibsky are very very similar players with similar ceilings, then they had no reason to not take that deal. They could've got their guy along with more assets, and we could've fixed our PF jam and added Winslow. It makes too much sense for everyone involved. Surely KO was at least brought up as a possibility.
I'm sure Ainge brought him up but Olynyk is only signed for two more years whereas Kaminsky will obviously be around for at least four. Also, Kaminsky is younger by two years.
I'm also surprised to see that Olynyk actually wasn't a big 3-pt. shooter in college and so far hasn't really made that a reliable weapon in the NBA either. Kaminsky actually avg'd 1.1 a game and 41.6% his final year in college. In 3 college years Olynyk never shot more than 0.3 3s a game and had a total of 25 3s his total collegiate career.
Still, I get your point that Olynyk and Kaminsky are similar "types." Obviously the Bobcats either didn't do enough research on Olynyk, thought the contract difference was significant, thought Kaminsky was better, or all of the above. I suspect Jordan just liked Kaminsky better, and that combined with their unpreparedness led them to turn it down.