Hi,
For (1), keep the Quest Editor window open during play. Click on whatever GameObject has the player's Quest Journal component. When a quest gets added to the player's Quest Journal, its nodes will appear in the Quest Editor window. Make sure there's only one Quest Journal component in the scene. You can enter "t:QuestJournal" in the Hierarchy's search bar to show all GameObjects with Quest Journal components. (It's technically possible to have multiple Quest Journals, but for a single player game you should only have one.) Also inspect the Quest Journal component's Quests list. When the NPC gives the quest, it should appear in the Quests list. If it doesn't, double check the Console window. Make sure warnings aren't being filtered out.
For (2), check if your EventSystem's "Submit" input is mapped to the "E" key. If so, then maybe the "(J)ournal" button in the top left of the screen is currently selected by the EventSystem. Pressing the "Submit" input in this case would click the button. You've probably noticed this warning in the Console window: "Dialogue System: The scene is missing an EventSystem. Adding one." To resolve this, add an EventSystem to the scene. (Menu item GameObject > UI > EventSystem.) If that's not it, check the button for a UI Button Key Trigger component. This component can map an input as a hotkey for the button.
For (3), that looks like the Save System Test Menu. If you inspect the Save System Test Menu component, you'll see that the Menu Input Button is probably set to "Cancel". Invector remaps the "Cancel" input to the Backspace key. You may want to remap it back. If you can't click on the buttons, make sure the OnShow() and OnHide() UnityEvents are configured in the inspector like they are in the Invector integration's "Shooter Example" scene. If you can click them but they don't do anything, check the Console window for errors or warnings.
Also make sure your scene has a Save System component. The quickest way to set up the Save System component is to download the SaveSystemPrefabs package (
direct download) from the
Dialogue System Extras page. Import it and add the Save System prefab to your scene. Then add the LoadingScreen scene to your project's build settings.