Concerning your concern with not being able to see the footer - can you get around this by fixing the footer to the bottom of the view port, and then adjusting the height of the main of the container to account for this space? You would have to modify your scrollHandler function to account for the new "bottom" of the scroll-able area - to trigger the new server call.
I suppose, from looking at your code, that you could instead adjust the pixel buffer amount to account for the extra height needed, though that might have other side effects if I'm apprising it correctly in being the buffer height from the bottom of the view port at which scrolling begins.
Concerning your concern with not being able to see the footer - can you get around this by fixing the footer to the bottom of the view port, and then adjusting the height of the main of the container to account for this space? You would have to modify your scrollHandler function to account for the new "bottom" of the scroll-able area - to trigger the new server call.
I suppose, from looking at your code, that you could instead adjust the pixel buffer amount to account for the extra height needed, though that might have other side effects if I'm apprising it correctly in being the buffer height from the bottom of the view port at which scrolling begins.