Throwing some ideas out here. Since your bacteria are already fluorescent, you might not be able to do an "inside-outside" antibody staining since you'll require additional fluorescent channels and looks like.you already are using up red and.green channels.

If you have access to a confocal, you could do some 3d reconstruction or just some orthogonal views of z-stacks and that could indicate surface bacteria vs intracellular bacteria, pending you label your cells with something that will label the cell borders (i think fluorescent phalloidin could work to delineate cell borders)