Is there a way to ignore a change in the resource name? For example, I've changed my naming convention on something like an S3 bucket and I don't want to replace all of the existing ones, but new ones will have it. opts+ignoreChanges does not seem to be really ignoring it as it still wants to delete and replace.

You can use aliases. Docs are here: https://www.pulumi.com/docs/intro/concepts/resources/#aliases and there's a great blog post on refactoring using aliases here https://www.pulumi.com/blog/cumundi-guest-post/

Aliases apply to the Pulumi name (1st parameter to constructor). If you mean the resource name in your cloud provider (e.g. the "bucket" property of an S3 bucket), then ignoreChanges should work.