Using version 14. @page-float-bottom content is not showing up.

                @page-float-top {
                    content: "page-float-top";
                }

Any guidance on how to get this to work is appreciated.

Sorry for any confusion. I'm struggling with both @page-float-top and @page-float-bottom.

For page headers/footers you can use the @top-center / @bottom-center page regions. Prince doesn't support generated content on the page float region, you can create page floats with the float property on a regular element.