So the only situation that could occur based on publishing before registration is complete that couldn't otherwise occur is also having infringement occur before registration is complete. In that situation, you wouldn't be able to seek statutory damages or attorney's fees for the infringement.
What I'm more asking is, if someone infringes between the date of publication and the completed copyright registration, would I then be able to sue for full damages
after the registration
does go through? Or does it basically just create this weird legal blindspot, in which there's basically proof of both copyright and infringement, but since the proof itself wasn't officiated until afterwards, it just...doesn't count, for some reason?
Effective Date of Registration
When the Copyright Office registers a work it assigns an effective date of registration to the certificate of registration. The effective date of registration is the day that the Office receives in proper form all required elements - an acceptable application, an acceptable deposit, and a nonrefundable filing fee. The date is not set until all the required elements are in the Office's possession...The date is not based on how long it takes the Office to examine the materials or mail the certificate of registration.
You do not have to receive your certificate of registration before you publish or produce your work. Nor do you need permission from the Copyright Office to place a copyright notice on your work.
From the US Copyright Office Circular 1 Copyright Basics: https://www.copyright.gov/circs/circ01.pdf#page=7
I guess what I really want to know is less "may I legally do this?," and more
"is it a good idea?" Should I go ahead and publish as soon as the copyright office tells me they have everything they need, or should I just be patient and wait those three extra months? What can people do to exploit me if I try and take a shortcut like this, how likely are they to do it, and what all am I likely to lose if they do? Or, am I just being paranoid, and is this not actually a 'shortcut' at all?