As for Question #1. You're in for some work. I'm going to assume that your forums are located at
www.yourdomain.com/forum. The redirect comes when folks hit
www.yourdomain.com, correct?
Basically, you'll have to move your entire forum to the root directory of your domain structure, e.g. /public.html and change your config.php to reflect this change. You'll also have to change all the domain pointers in AdminCP. Quite a bit of work. What you can do is knock down the time in your index.html located at root and have it immediately redirect, instead of waiting the couple of seconds.
As for Question #2, never looked into that. Not sure which template you'd have to edit.