Vertically align to bottom epub

No. There are no 'hooks' for knowing the height of a reflowable page or positioning at any point between the virtual page break and the bottom.

You can only use top spacing to push content down, and use judgment and testing to determine if it will be near the bottom but not breaking to the next page on smaller page displays. (Which will be bypassed if the use makes the reader window smaller or increases font size or spacing.)

I generally scale things like title and copyright pages to remain comfortably within the Kindle E-Reader mode using Kindle Previewer. That leaves bottom content somewhat higher on the larger pages, but it's the best all around compromise.