Is there a way to access a value in a stack output object in a Stack README? The documentation mentions plain old outputs, as well as indexing into array outputs, but seems to be silent on objects.

You should be able to use the same property path syntax that is documented here for ignore changes: https://www.pulumi.com/docs/intro/concepts/resources/options/ignorechanges/

@lemon-agent-27707 looks like that did the trick; thanks!