2. Also, how do you change the text in the column header - for example, "Related To"?
Thanks!
3 answers
Rosanna,
As far as I know, you can do none of those since all of the entities you mentioned (button, column heaaders etc.) are standard SF activity functionality and you are not allowed to edit their labels.
You can certainly create a new button labeled 'Log Activity' though (which would require code to implement).