To answer my own question, I guess one possible solution is to use the manual setting and place the function that calls the buttons inside the post/page templates. This requires the use of multiple templates, which is ok, I guess.
Another solution would be to use a plugin like widget logic and place the buttons in widget areas, however, in my case I would have to create a new widget are.
I suppose the hack I was trying to use didn't work because the filter acts on content, which is inside the loop, so it isn't possible to use a conditional is_page statement to limit this, however I am still wondering if there is some way to exclude certain pages in the code itself, without having to create new widget areas or potentially, new page templates.
If the above is indeed possible, I have a feature suggestion:
add a dropdown to the GUI that excludes certain pages or page types (templates). Also potentially post types.
This may be a real pain, but I'm just spitballing here. I am curious to know what your thoughts are here.
Love th plugin by the way.