When is a form too long for slide-out panels vs. modals vs. full-page? [closed]

Question

I am designing effectively a new experience for our administration interface, and there are several places where the user is on a list page of some sort, and some core tasks are to create or edit objects.

For the most part these are very short forms - Name, some details about the object to be created or edited, save/cancel - and I am considering implementing a slide-in modal panel (or drawer) pattern for exposing these forms from the appropriate context.

So the basic flows goes:

• View list of objects >
• Create new object >
• Form slides in to gather basic info about the new object >
• When complete, user clicks Save and either sees - in simple cases - a confirmation and the object is added to the list, or in more complex cases is taken directly to a configuration page for the new object.

To visualize it, the main list page might look something like this:

And upon clicking "Add Object", the drawer would slide out to allow the user to enter details:

This will be an entirely desktop-based experience, it is unlikely there will ever be a mobile version of this software - though there are other touchpoints in both mobile and physical device UIs that need to stay at least moderately consistent with the overall experience (though as of now we don't expect most users to ever use all of them - the core user for this experience will primarily use only this experience)

The basic questions are these:

1. When does a form become too long to be usably handled in a modal-type experience and the user should be taken to a new page to complete the form? Most of these forms are short like the one pictured, and look "floaty" if presented alone on a new desktop page.
2. Is it kosher to "chunk" a longer form in this sort of experience, making it sort of "wizard-like" and taking the user through multiple steps in the same modal/panel?
3. Any arguments for using a more traditional window-style modal instead of the slide-in panel? We tend to avoid them except for simple confirmation- and dialog-type situations, and SOME of these forms can get longer, but I am open to arguments.
4. Any reason such a form should NOT be modal, but allow the user to click out to dismiss it? I don't see why, the user has triggered the function and intends to complete the form... but any devil's advocates out there think it should be NON-modal?

Thanks in advance!