Hmm..... I'll see if I can have a try answering you.
1.) I don't know of any fix, mine was running non 3.6.8 pl2 fine without any fix as far as I know. But I'm not sure if my users used the quickreply so maybe you need the fix.
2.) That's normal behaviour, a merge post is in fact not a new post but an edited post. Edited post do not show up as new posts.
3.) A few more users asked that one, so we have to wait until somebody answers how to code such line.
I was not much of a help for you, except maybe by explaining question 2, but he... every little bit of help is something.