Hi, @blair.carbonzero. To answer this specific question:
If we test our current build to see if it will work on Focal out-of-the-box and it fails, will we be able to switch it back to Xenial between now and the end-of-support date until we get a dev to look at it and make the necessary changes?
Yes, you can still change back to Xenial up to October 18th as documented here. We will not disable that option before that day. After that day any upgrade cannot be downgraded again.