Page-Links Plus appears to be working fine with my WordPress 4.7 theme ‘Layout-Builder’ (child from sg-window). Although PLP warns that the function wp_link_pages is not found in the theme, which is correct as the function is located in the parent theme, the PLP page links work!
The Page links are positioned at the bottom of the content.
I would also like to see them at the top at the beginning of the content. That way the users know upfront that there is more than one page to view and users who visited before and know they want to visit for example the last page don’t have to scroll all the way to the bottom of the first page to select the page link.