The fields you pointed out are all optional, they are not the ones causing the issue.
From the screen shots you sent I don't see anything wrong...
When you say the UI is unresponsive you mean the hovering/clicking does not work at all right? Usually when that happens it is because there is a transparent image covering up the UI. I see that you have two other canvas on top of the Inventory one. Is there any chance one of them is covering it up blocking raycasts? Try disabling them to see if that works.
That being said your UI does not seem to load the inventory... either. You seem to be using UMA, is your character spawned at runtime?
You cannot set a prefab as the Display Panel Owner. Maybe that is what causing the issue.
A few users have pointed out that spawning a character at runtime causes issues. This something that will be fixed in the next patch, I've already wrote the code for it, but we won't be updating UIS for another few weeks.
If you want to spawn your character at runtime before the next update you must follow a few steps:
1) Disable the DisplayPanelManager gameobject (the parent to all UI) in your scene
2) Spawn the player character at runtime
3) In code assign the player as the panel owner of Display Panel Manager
4) Only after the panel owner is set enable the Display Panel Manager gameobject
In the next update the UI and the player will be able to find each other using IDs. And it won't matter which one is spawned first.
I hope that fixes your issues
Note for the next update: You do not have to remove the UI in your scene when you update the schema for UI Designer. UI Designer is just there to help you build the UI, the UI does not need UI Designer to work. That being said there are some little improvements here when spawning new objects from UI Designer now compared to before.
Also, just a reminder to always make a backup before updating any asset. You can always revert the changes if there is an issue