Want to make your site migrations go much smoother? Before going live, perform a crawl of your site on Screaming Frog and save it. You now have:
1. All previous URL paths
2. All previous title tags, meta descriptions, H1s etc
3. Insight into previous structured data implementation
4. Site performance benchmarks of the old site
5. A list to recrawl to ensure your redirects are properly implemented
Taking this one step has saved me a lot of headache when doing migrations throughout the years