Good long list of stuff.
6. If you walk one step at a time, you won't fall on the ice. Trying to run across will make you have to roll a saving throw against falling.
15. That area is working properly. You just haven't figured it out yet. It's quite a tricky puzzle.
I agree that walking over the stones does spare you from falling, but if you notice there is a roll to see if you slip when running, and every time you save roll fails, without fail. Also, when you are running out of combat, it is a bit frustrating, since your followers AI seemingly runs right into the ice despite your lead character running far around the ice. That goes back to my other statement that the followers run too far behind.
Can you PM me what I am missing with the statue quest, so it is not posted on the forum as a spoiler? Also, did you figure out the talking statues?