Hmm… there was never support for Odin Inspector in NodeCanvas to be honest 🙂 NodeCanvas only ever supported its own custom made attributes for inspectors. What does a [ShowInInspector] attribute does in Odin please? (I can implement that for you in NodeCanvas and send it to you if you want).
If you want to take full control of a specific node or task inspector without relying on implementing attributes drawers, you can overriding the protected void OnNodeInspectorGUI for nodes (or OnTaskInspectorGUI for tasks) and create a custom inspector for that node/task in there.
Out of curiocity, what was the previous NodeCanvas version that you were using?