Hi
Question 1:
Edit the view, just above the View Representation box is a check box that looks like a chain link, Uncheck this box.
NOTE: This is the associative box, which automatically updates design view reps in the model. Inventor is using this a lot more, so try and start using it by setting the visiblity of components in the assembly/part.
Question 2
I am not sure if this is possible, but following is what I do to solve this issue:
This is a 2 stage process.
Create a new leader style with a white line style. (Page colour)
Create a new Balloon style
Change the leader to the new "White" leader created above.
You can now switch between the 2 balloon styles by selecting the balloon style from the "Format" pulldown.
Hope this help.