Recommendations on converting a page on old platform to new platform

I have several pages that were created on the old platform. Those pages are getting long and cumbersome so I want to use accordians and page anchors. If I create new pages with that functionality available, the page link will change. Other pages in our intranet link to these old-platform pages, so those links will be broken. Is there a way to assign the link for a new page (so I can keep the old URLs)? Is there a way to find out what other pages in the intranet link to the old-platform pages so I can easily update to the new URL?